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Last Updated :2024/10/10

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Master

Affiliation (Master)

  • Faculty of Science　Institute of Seismology and Volcanology

Affiliation (Master)

  • Faculty of Science　Institute of Seismology and Volcanology

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Profile and Settings

Degree

  • Master of Science（1998/03 The University of Tokyo）
  • Doctor of Science（2001/03 The University of Tokyo）

Profile and Settings

  • Name (Japanese)

    Aoyama

  • Name (Kana)

    Hiroshi

  • Name

    200901052088458239

Achievement

Research Interests

  • 火山地震学   火山物理学   Volcano Observation   Volcano Eruption   Infrasound   Debris Flow   Volcano Seismology   Volcano Physics   Volcano Monitoring   

Research Areas

  • Natural sciences / Solid earth science / Volcano Physics, Volcano Erption, Volcano Monitoring, Eruption Prediction, Seismology, Hydrothermal Systems

Research Experience

  • 2023/04 - Today 東京大学地震研究所 附属観測開発研究センター 客員教授
  • 2021/04 - Today Hokkaido University
  • 2020/07 - Today Hokkaido University Institute of Seismology and Volcanology Faculty of Science Professor
  • 2022/01 - 2024/03 National Research Institute for Earth Science and Disaster Prevention Center for Integrated Volcano Research Senior Research Fellow
  • 2020/04 - 2021/03 Japan Meteorological Agency Advisor
  • 2017/10 - 2020/06 Hokkaido University Institute of Seismology and Volcanology, Faculty of Science Associate Professor
  • 2018/04 - 2020/03 Earthquake Research Institute, the University of Tokyo Volcano Research Center Visiting Associate Professor
  • 2007/04 - 2017/09 Hokkaido University Institute of Seismology and Volcanology, Faculty of Science Assistant Professor
  • 2011/04 - 2017/03 Muroran Institute of Technology Division of Engineering Lecturer (part-time)
  • 2006/04 - 2007/03 Hokkaido University Institute of Seismology and Volcanology, Faculty of Science Assistant Professor
  • 2001/04 - 2006/03 Hokkaido University Institute of Seismology and Volcanology, Graduate School of Science Assistant Professor

Education

  • 1998/04 - 2001/03  The University of Tokyo  Graduate School of Science  Department of Earh and Planetary Physics (Docter)
  • 1996/04 - 1998/03  The University of Tokyo  Graduate School of Science  Department of Earh and Planetary Physics (Master)
  •        - 1996/03  Hokkaido University  School of Science  Geophysics

Awards

  • 2022/05 Volcanological Society of Japan Best Paper Award
     The 2018 phreatic eruption at Mt. Motoshirane of Kusatsu–Shirane volcano, Japan: eruption and intrusion of hydrothermal fluid observed by a borehole tiltmeter network 
    受賞者: Akihiko Terada;Wataru Kanda;Yasuo Ogawa;Taishi Yamada;Mare Yamamoto;Takahiro Ohkura;Hiroshi Aoyama;Tomoki Tsutsui;Shin’ya Onizawa

Published Papers

  • Taishi Yamada, Akihiko Terada, Rina Noguchi, Wataru Kanda, Hideki Ueda, Hiroshi Aoyama, Takahiro Ohkura, Yasuo Ogawa, Toshikazu Tanada
    Journal of Geophysical Research: Solid Earth 128 (11) 2169-9313 2023/10/27 [Refereed][Not invited]
     
    Triggering intrusions of phreatic eruptions are often observed as seismic and ground deformation signals on a time scale of minutes. The current understanding of hydrothermal intrusions still needs improvement to obtain insight into the eruption scale from the observables. We examine local geophysical data from the precursory hydrothermal intrusion of the 2018 phreatic eruption of Kusatsu‐Shirane volcano. To achieve an integrated intrusion model, we divide analyzing time window into the onset, middle, and climax. Focusing on the transient response of tilt data for the sudden pressurization, we estimate a vertical tensile opening (1.7 × 103 m3/s in 40 s) at 1.1 km depth for the intrusion onset. Pressurization can represent the start of vapourization. Very long period (VLP, 0.033–0.1 Hz) seismic signals are adopted to constrain the middle and climax phases. We obtained two sequential semi‐horizontal tensile crack oscillation sources with peak volume changes of 3.6 × 104–1.9 × 105 m3 at 0.3–0.6 km depths. The second VLP source acted as a final trigger of the eruption to cause depressurization in the shallow portion of the intruded region, which is constrained as having reached 0.1 km depth by surface deformation. Simultaneously, we find another depressurization originated from depth in the climax due to a decrease in the hydrothermal intrusion rate. Through comparison with the 2014 Ontake phreatic eruption, the total inflation volume may correlate with eruption scales. Intruded hydrothermal fluid and local structure characteristics also may have to be considered to evaluate the eruptions scales from inferred signal source intensity.
  • 1999 年伊豆大島における人工地震探査 ─観測および初動走時データによる3 次元地震波速度構造─
    渡辺秀文, 鍵山恒臣, 坂下至功, 及川 純, 大湊隆雄, 小山悦郎, 辻 浩, 宗包浩志, 松下誠司, 萩原道徳, 竹田豊太郎, 長田 昇, 井本良子, 青山 裕, 浜田盛久, 趙 燕来, Mossa Hesham, 福満修一郎, 青木重樹, 藤原健治, 池田 靖, 加治屋秋実, 安藤 忍, 亀井 守, 古田雅和, 浅沼光輝, 佐藤勝良, 山賀一章, 石脇 誠, 広瀬淳司, 干場三寛, 福田 直, 坂 勝仁, 森 済, 勝俣 啓, 前川徳光, 岡田 弘, 田中 聡, 山脇輝夫, 仁田交市, 橋野弘憲, 野津憲治, Pedro A. Hernandez, 下池洋一, R. Noemi Lima, 野上健治, 平林順一, 鈴木 隆, 熊谷博之, 奥田 隆, 戸松稔貴, 河村 将, 松島 健, 栗山 都, 永野 一, 高木朗充, 筒井智樹, 須藤靖明, 吉川 慎, 吉川美由紀, John Macario Londono, 井口正人, 為栗 健, Janauar Herry Setiawan, 宮町宏樹, 平野舟一郎, 水原健太郎, 鶴我佳代子
    地震研究所彙報 98 1 - 29 2023/10 [Refereed]
  • Ayuta Tsuge, Hiroshi Aoyama, Kenji Nogami, Fujio Akita, Kazuhiko Kato
    Journal of Volcanology and Geothermal Research 440 107851 - 107851 0377-0273 2023/08 [Refereed]
  • Matsuda Mizuki, Ohzono Mako, Aoyama Hiroshi, Tanaka Ryo, Hirado Yuto, Okada Kazumi, Takahashi Hiroaki
    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN 特定非営利活動法人 日本火山学会 2023 149 - 149 2433-5320 2023
  • Theodorus Permana, Hiroshi Aoyama
    Seismological Research Letters 94 (2A) 871 - 886 0895-0695 2022/11/23 [Refereed][Invited]
     
    Abstract Volcanic tremors and earthquakes must be monitored to gain insights into volcanic activity. Localization of their sources is often challenging because of the unclear onset of seismic waves, particularly when the volcanic activity increases before and during an eruption. Existing alternative techniques to locate the seismic sources are based on the information on the spatial amplitude distribution or the travel-time difference of seismic waves. Exploring the idea of combining both information for source location determination, we propose a new location method that uses the amplitude and travel-time difference information obtained from the unnormalized cross correlations of seismic data. Evaluation using volcanic earthquakes that occurred in 2020 at Tokachidake volcano, Japan, reveals an improvement in location accuracy compared to existing methods using individual information. Analysis of an episode of volcanic tremors and earthquakes accompanying a rapid tilt change event on 14 September 2020 reveals that during the inflation of the crater area, reliable seismic source locations with an error of ≤1 km become more concentrated at around 0.6 km beneath the 62-2 crater, in which the most recent eruptive activity had occurred. Such changes in source locations are associated with the movement of volcanic gas and hot water from the hydrothermal system below. Our proposed method is useful for locating and monitoring seismic source locations corresponding to volcanic fluid movements.
  • IKEDA Wataru, ICHIHARA Mie, HONDA Ryo, AOYAMA Hiroshi, TAKAHASHI Hidetoshi, YOSHIMOTO Mitsuhiro, SAKAI Shin'ichi
    Journal of the Japanese Society of Snow and Ice 公益社団法人 日本雪氷学会 84 (5) 421 - 432 0373-1006 2022/09/15 [Refereed][Not invited]
     
    We tried infrasonic monitoring of snow avalanche at Mt. Fuji. We installed infrasound sensors, a thermometer-probe snow-depth meter, and seismometers for two winter seasons from 2018 to 2020 and made integrated analyses of their data. Although no significant snow avalanche event occurred during our observation, we found many infrasound waveforms similar to the reported snow avalanche infrasound. Because the infrasound events accompanied little seismic power, we inferred surface phenomena, if not necessarily snow avalanches, generated them. The events’ occurrences were concentrated during and right after snow-falls and during snow melting. The infrasonic array analyses of the 2019-2020 dataset exhibited most of the events are from the north slopes below the observation site. From the summit direction, continuous infrasonic noise was frequently detected, by which detecting events from there might have been difficult. This study has shown that the multi-parameter observation method is practical and useful in the severe environment of Mt. Fuji in winter. Also, it revealed the particular problems of infrasound observation at the huge volcanic edifice. We expect our results will help design future observations.
  • 青山 裕
    火山 日本火山学会 67 (2) 171 - 193 2022/06/30 [Refereed][Not invited]
  • Akiko Takeo, Kiwamu Nishida, Hiroshi Aoyama, Motoko Ishise, Takeru Kai, Ryo Kurihara, Takuto Maeda, Yuta Mizutani, Yuki Nakashima, Shogo Nagahara, Xiaowen Wang, Lingling Ye, Takeshi Akuhara, Yosuke Aoki
    Geophysical Journal International 230 (3) 1662 - 1678 0956-540X 2022/05/19 [Refereed][Not invited]
     
    SUMMARY To obtain an internal S-wave velocity structure, we conducted a passive seismic campaign with 21 1-Hz seismometers on and around the Showa-Shinzan lava dome, which emerged during the 1943–1945 eruption of Usu Volcano, Japan. Before the campaign, we calibrated seismometers and found slight phase-response differences between seismometers of less than 1–2°. After the campaign, we extracted seismic wavefield by taking cross-correlations of vertical-component ambient noise records between seismic sites. We developed a new method to measure phase velocities of the Rayleigh wave automatically by assuming layered structure and finally obtained 1-D S-wave velocity models in summit, roof and base regions. The obtained S-wave velocity right beneath the intruded lava dome is higher than that in surrounding areas by a few tens of per cent down to a few hundred metres below sea level, indicating narrow but deep existence of the root of the lava dome. The obtained S-wave velocity at depths shallower than ∼50 m inside the lava dome in the summit area was ∼1 km s−1, significantly lower than that predicted from the density of  2.3 × 103 kg m−3 estimated in previous muon-radiography studies and a conventional scaling, indicating the effect of cracking in the lava dome.
  • Akihiko Terada, Wataru Kanda, Yasuo Ogawa, Taishi Yamada, Mare Yamamoto, Takahiro Ohkura, Hiroshi Aoyama, Tomoki Tsutsui, Shin’ya Onizawa
    Earth, Planets and Space 73 (1) 157  2021/06/30 [Refereed][Not invited]
     
    AbstractWe estimate the mass and energy budgets for the 2018 phreatic eruption of Mt. Motoshirane on Kusatsu–Shirane volcano, Japan, based on data obtained from a network of eight tiltmeters and weather radar echoes. The tilt records can be explained by a subvertical crack model. Small craters that were formed by previous eruptions are aligned WNW–ESE, which is consistent with the strike of the crack modeled in this study. The direction of maximum compressive stress in this region is horizontal and oriented WNW–ESE, allowing fluid to intrude from depth through a crack with this orientation. Based on the crack model, hypocenter distribution, and MT resistivity structure, we infer that fluid from a hydrothermal reservoir at a depth of 2 km below Kusatsu–Shirane volcano has repeatedly ascended through a pre-existing subvertical crack. The inflation and deflation volumes during the 2018 eruption are estimated to have been 5.1 × 105 and 3.6 × 105 m3, respectively, meaning that 1.5 × 105 m3 of expanded volume formed underground. The total heat associated with the expanded volume is estimated to have been ≥ 1014 J, similar to or exceeding the annual heat released from Yugama Crater Lake of Mt. Shirane and that from the largest eruption during the past 130 year. Although the ejecta mass of the 2018 phreatic eruption was small, the eruption at Mt. Motoshirane was not negligible in terms of the energy budget of Kusatsu–Shirane volcano. A water mass of 0.1–2.0 × 107 kg was discharged as a volcanic cloud, based on weather radar echoes, which is smaller than the mass associated with the deflation. We suggest that underground water acted as a buffer against the sudden intrusion of hydrothermal fluids, absorbing some of the fluid that ascended through the crack.
  • 1950年代に雌阿寒岳山上で取得されたすす書き地震記録の再解析
    丹羽俊介, 青山 裕, 澤田可洋
    釧路市立博物館紀要 39 63 - 75 2021/03 [Not refereed]
  • Taishi Yamada, Aika Kurokawa, Akihiko Terada, Wataru Kanda, Hideki Ueda, Hiroshi Aoyama, Takahiro Ohkura, Yasuo Ogawa, Toshikazu Tanada
    Earth, Planets and Space 73 (1) 14  2021/01/11 [Refereed][Not invited]
     
    AbstractKusatsu-Shirane volcano hosts numerous thermal springs, fumaroles, and the crater lake of Yugama. Hence, it has been a particular study field for hydrothermal systems and phreatic eruptions. On 23 January 2018, a phreatic eruption occurred at the Motoshirane cone of Kusatsu-Shirane, where no considerable volcanic activity had been reported in observational and historical records. To understand the eruption process of this unique event, we analyzed seismic, tilt, and infrasound records. The onset of surface activity accompanied by infrasound signal was preceded by volcanic tremor and inflation of the volcano for ~ 2 min. Tremor signals with a frequency band of 5–20 Hz remarkably coincide with the rapid inflation. We apply an amplitude source location method to seismic signals in the 5–20 Hz band to estimate tremor source locations. Our analysis locates tremor sources at 1 km north of Motoshirane and at a depth of 0.5–1 km from the surface. Inferred source locations correspond to a conductive layer of impermeable cap-rock estimated by magnetotelluric investigations. An upper portion of the seismogenic region suggests hydrothermal activity hosted beneath the cap-rock. Examined seismic signals in the 5–20 Hz band are typically excited by volcano-tectonic events with faulting mechanism. Based on the above characteristics and background, we interpret that excitation of examined volcanic tremor reflects small shear fractures induced by sudden hydrothermal fluid injection to the cap-rock layer. The horizontal distance of 1 km between inferred tremor sources and Motoshirane implies lateral migration of the hydrothermal fluid, although direct evidence is not available. Kusatsu-Shirane has exhibited unrest at the Yugama lake since 2014. However, the inferred tremor source locations do not overlap active seismicity beneath Yugama. Therefore, our result suggests that the 2018 eruption was triggered by hydrothermal fluid injection through a different pathway from that has driven unrest activities at Yugama.
  • Yuki Susukida, Kei Katsumata, Masayoshi Ichiyanagi, Mako Ohzono, Hiroshi Aoyama, Ryo Tanaka, Masamitsu Takada, Teruhiro Yamaguchi, Kazumi Okada, Hiroaki Takahashi, Shin’ichi Sakai, Satoshi Matsumoto, Tomomi Okada, Toru Matsuzawa, Hiroki Miyamachi, Shuichiro Hirano, Yoshiko Yamanaka, Shinichiro Horikawa, Masahiro Kosuga, Hiroshi Katao, Yoshihisa Iio, Airi Nagaoka, Noriko Tsumura, Tomotake Ueno
    Earth, Planets and Space 73 1  2021/01/01 [Refereed][Not invited]
     
    AbstractThe tectonic stress field was investigated in and around the aftershock area of the Hokkaido Eastern Iburi earthquake (MJMA = 6.7) occurred on 6 September 2018. We deployed 26 temporary seismic stations in the aftershock area for approximately 2 months and located 1785 aftershocks precisely. Among these aftershocks, 894 focal mechanism solutions were determined using the first-motion polarity of P wave from the temporary observation and the permanent seismic networks of Hokkaido University, Japan Meteorological Agency (JMA), and High Sensitivity Seismograph Network Japan (Hi-net). We found that (1) the reverse faulting and the strike-slip faulting are dominant in the aftershock area, (2) the average trend of P- and T-axes is 78° ± 33° and 352° ± 51°, respectively, and (3) the average plunge of P- and T-axes is 25° ± 16° and 44° ± 20°, respectively: the P-axis is close to be horizontal and the T-axis is more vertical than the average of the P-axes. We applied a stress inversion method to the focal mechanism solutions to estimate a stress field in the aftershock area. As a result, we found that the reverse fault type stress field is dominant in the aftershock area. An axis of the maximum principal stress (σ1) has the trend of 72° ± 7° and the dipping eastward of 19° ± 4° and an axis of the intermediate principal stress (σ2) has the trend of 131° ± 73° and the dipping southward of 10° ± 9°, indicating that both of σ1- and σ2-axes are close to be horizontal. An axis of the minimum principal stress (σ3) has the dipping westward of 67° ± 6° that is close to be vertical. The results strongly suggest that the reverse-fault-type stress field is predominant as an average over the aftershock area which is in the western boundary of the Hidaka Collision Zone. The average of the stress ratio R = (σ1 − σ2)/(σ1 − σ3) is 0.61 ± 0.13 in the whole aftershock area. Although not statistically significant, we suggest that R decreases systematically as the depth is getting deep, which is modeled by a quadratic polynomial of depth.
  • NAKAMICHI, Haruhisa, YAMAMOTO, Keigo, YAMADA, Taishi, TAMEGURI, Takeshi, TAKAHASHI, Kousuke, AOYAMA, Hiroshi, YAMAMOTO, Mare, NOGAMI, Kenji, OIKAWA, Jun, MAEDA, Yuta, OHKURA, Takahiro, MATSUSHIMA, Takeshi, YAKIWARA, Hiroshi, SUGAHARA, Michitomo, TSUKAMOTO, Kaori, KISHIMOTO, Hiroshi, KUDO, Naoki, YAMAMURA, Takuya, HIRAHARA, Satoshi, YAGI, Takeo, HORIKAWA, Shinichiro, YOSHIKAWA, Shin, SONODA, Tadaomi, NAKATANI, Yukihiro, HIRANO, Shuichiro, MIYAMACHI, Hiroki, TANAKA, Yuki, YOSHIDA, Hideomi, NISHIKAWA, Sora, KAI, Takeru, TAKAHASHI, Ryuhei, TANOUE, Kazushi, KAWABE, Satoshi, WAKABAYASHI, Tamaki, MURAMATSU, Dan, HASHIMOTO, Tasuku, OSUGA, Keishi
    Disaster Prevention Research Institute Annuals. B 京都大学防災研究所 63 (B) 100 - 107 0386-412X 2020/12 
    We conducted an active seismic experiment in Sakurajima volcano in December 2019, three years after the similar experiment that was conducted in 2016. We deployed 185 temporary seismic stations, most of which were installed at the same place as in 2013 and 2016. Eight and two explosive shots with 20 and 100 kg charges, respectively, were detonated in December 5, 2019. The 2019 shot locations differ from 0.4 to 12 m from the corresponding previous shot locations. We successively observed the all explosions during nighttime nine hours continuous recording. We examine reflection phases on the seismic records that obtained by the previous and 2019 experiment to detect temporal change of subsurface seismic structure beneath Sakurajima volcano.
  • Aoyama Hiroshi, Tanaka Ryo, Hashimoto Takeshi, Murakami Makoto, Narita Shohei
    Geophysical bulletin of Hokkaido University 北海道大学大学院理学研究院 83 (83) 25 - 48 0439-3503 2020/03/19 [Not refereed][Not invited]
  • Kudo Chisato, Aoyama Hiroshi, Tanaka Ryo
    Geophysical bulletin of Hokkaido University 北海道大学大学院理学研究院 83 103 - 114 2020/03/19 [Not refereed][Not invited]
  • Tsuge Ayuta, Aoyama Hiroshi
    Geophysical bulletin of Hokkaido University 83 49 - 70 2020/03/19 [Not refereed][Not invited]
  • T. Hashimoto, W. Kanda, Y. Morita, M. Hayakawa, R. Tanaka, H. Aoyama, M. Uyeshima
    Journal of Disaster Research 14 (4) 580 - 591 1881-2473 2019/06 [Refereed][Not invited]
     
    The detection capability of various anomalous phenomena preceding volcanic eruptions has considerably progressed as the geophysical monitoring networks have become denser and multi-disciplinary. However, current eruption forecasting techniques, from a practical perspective, still have much scope for improvement because they largely depend on empirical techniques. In the past decade, three-dimensional modeling based on the electromagnetic sounding methods such as magnetotellurics (MT) have become a practical choice, and its recent applications to active volcanic fields has revealed certain common features among volcanoes. Information about the resistivity structure, especially in 'wet' volcanic fields, is useful for the provisional screening of the eruption potential from the viewpoint of the subsurface structure, and, thus, may contribute to the evaluation of eruption imminence in a broad sense. In this study, for evaluation purposes, we present the roles and possible further applications of the subsurface resistivity structure studies by demonstrating the preliminary results and interpretations of an MT survey that we performed in the Kuttara Volcanic Group, northern Japan.
  • K. Katsumata, M. Ichiyanagi, M. Ohzono, H. Aoyama, R. Tanaka, M. Takada, T. Yamaguchi, K. Okada, H. Takahashi, S. Sakai, S. Matsumoto, T. Okada, T. Matsuzawa, S. Hirano, T. Terakawa, S. Horikawa, M. Kosuga, H. Katao, Y. Iio, A. Nagaoka, N. Tsumura, T. Ueno, the Group for the Aftershock Observations of the 2018 Hokkaido Eastern Iburi Earthquake
    Earth Planets Space 71 53  1880-5981 2019/05 [Refereed][Not invited]
     
    The Hokkaido Eastern Iburi earthquake (M-JMA=6.7) occurred on September 6, 2018, in the Hokkaido corner region where the Kurile and northeastern Japan island arcs meet. We relocated aftershocks of this intraplate earthquake immediately after the main shock by using data from a permanent local seismic network and found that aftershock depths were concentrated from 20 to 40km, which is extraordinarily deep compared with other shallow intraplate earthquakes in the inland area of Honshu and Kyushu, Japan. Further, we found that the aftershock area consists of three segments. The first segment is located in the northern part of the aftershock area, the second segment lies in the southern part, and the third segment forms a stepover between the other two segments. The hypocenter of the main shock, from which the rupture initiated, is located on the stepover segment. The centroid moment tensor solution for the main shock indicates a reverse faulting, whereas the focal mechanism solution determined by using the first-motion polarity of the P wave indicates strike-slip faulting. To explain this discrepancy qualitatively, we present a model in which the rupture started as a small strike-slip fault in the stepover segment of the aftershock area, followed by two large reverse faulting ruptures in the northern and southern segments.
  • Gen Kondo, Hiroshi Aoyama, Takeshi Nishimura, Maurizio Ripepe, Giorgio Lacanna, Riccardo Genco, Ryohei Kawaguchi, Taishi Yamada, Takahiro Miwa, Eisuke Fujita
    Scientific Reports 9 (1) 2019/04 [Refereed][Not invited]
  • Tiltmerer observation in Avachinsky volcano, Kamchatka, Russia
    Hiroaki TAKAHASHI, Hiroshi AOYAMA, Mako OHZONO, Ryo TANAKA, Chihiro ITO, Saki WATANABE, Takeshi MATSUSHIMA, Yusuke YAMASHITA, Hiroki MIYAMACHI, Satoshi OKUYAMA, EEvgeny GORDEEV, Yarosrav MURAVYEV, Kirill MAGUSKIN, Natalia MALIK, Ivan MINOROV, Danila CHEBROV
    Geophysical Bulletin of Hokkaido University 82 11 - 18 2019/03 [Not refereed][Not invited]
  • Taishi Yamada, Hiroshi Aoyama, Hideki Ueda
    Bulletin of Volcanology 80 (9) 71  2018/09 [Refereed][Not invited]
  • K. Yamakawa, M. Ichihara, K. Ishii, H. Aoyama, T. Nishimura, M. Ripepe
    Geophysical Research Letters 45 (17) 8931 - 8938 0094-8276 2018/08 [Refereed][Not invited]
  • Takeshi Hashimoto, Hiroshi Aoyama, Hiroshi Koyama, Atsushi Morii, Wataru Mishima, Tagiru Ogino, Ryo Takahashi, Noritoshi Okazaki
    Monthly Chikyu 40 (3) 163 - 169 0387-3498 2018/03 [Not refereed][Not invited]
  • J. Prudencio, T. Taira, Y. Aoki, H. Aoyama, S. Onizawa
    BULLETIN OF VOLCANOLOGY 79 (4) 29  0258-8900 2017/04 [Refereed][Not invited]
     
    We present intrinsic- and scattering-Q attenuation images for Usu volcano (Japan) by analyzing over 1800 vertical seismograms. By fitting the observed envelopes to the diffusion model, we obtained intrinsic and scattering attenuation values at three different frequency bands. Using a back-projection method and assuming a Gaussian-type weighting function, we obtained the 2D images of intrinsic and scattering attenuation. Resolution tests confirm the robustness and reliability of the obtained images. We found that scattering attenuation is the dominant process of energy loss in the frequency range analyzed, which suggests strong spatial heterogeneity. The resultant scattering attenuation images show an increase of attenuation toward the southwest from Toya caldera, which may correspond to deepening of the basement. We also identify an area of low intrinsic and scattering attenuation at the summit of Usu volcano which could be associated with old magma intrusions. Our results demonstrate a strong spatial relation between structural heterogeneities and attenuation processes in volcanic areas and confirm the efficiency of the method which can be used together with conventional imaging techniques.
  • 全磁力観測：火山体内部構造・熱水流動系のモデル化と火山活動度評価手法の高度化（十勝岳）
    橋本武志, 青山 裕, 田中 良
    北海道地質研究所調査研究報告 44 105 - 111 2017/03 [Not refereed][Not invited]
  • Hashimoto T., Matsumoto M., Aoyama H., Koyama H., Morii A., Mishima W., Ogino T., Takahashi R., Okazaki N.
    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN 特定非営利活動法人 日本火山学会 2017 36 - 36 2433-5320 2017
  • Taishi Yamada, Hiroshi Aoyama, Takeshi Nishimura, Masato Iguchi, Muhamad Hendrasto
    GEOPHYSICAL RESEARCH LETTERS 44 (1) 143 - 151 0094-8276 2017/01 [Refereed][Not invited]
     
    We examine very long period infrasonic signals accompanying volcanic eruptions near active vents at Lokon-Empung volcano in Indonesia, Aso, Kuchinoerabujima, and Kirishima volcanoes in Japan. The excitation of the very long period pulse is associated with an explosion, the emerging of an eruption column, and a pyroclastic density current. We model the excitation of the infrasound pulse, assuming a monopole source, to quantify the volume flux and cumulative volume of erupting material. The infrasound-derived volume flux and cumulative volume can be less than half of the video-derived results. A largely positive correlation can be seen between the infrasound-derived volume flux and the maximum eruption column height. Therefore, our result suggests that the analysis of very long period volcanic infrasound pulses can be helpful in estimating the maximum eruption column height.
  • Taishi Yamada, Hiroshi Aoyama, Takeshi Nishimura, Hiroshi Yakiwara, Haruhisa Nakamichi, Jun Oikawa, Masato Iguchi, Muhamad Hendrasto, Yasa Suparman
    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH 327 310 - 321 0377-0273 2016/11 [Refereed][Not invited]
     
    We examine the initial phases of explosion earthquakes accompanying Vulcanian eruptions at Lokon-Empung volcano in Indonesia to reveal the triggering process of explosive eruptions. In 2012-2013, 56 Vulcanian eruptions at Lokon-Empung were observed by our temporary observation network being comprised of four broadband seismometers and two infrasound microphones at 1.6-6.8 km from the active vent. The seismic records of each explosion earthquake share almost the same waveform characteristics of initial phases, consisting of a small compressional onset (P phase) and a subsequent large dilatational phase (D phase). Particle orbits of both phases show straight motion from beneath the active vent, which suggests that these phases are composed of a longitudinal body wave. For each explosion, the origin times of the P phase precedes 0.8-2.5 s before the occurrence of an explosion at the vent that are detected by infrasound data. Since the signal-to-noise ratio of the P phase is insufficient for a quantitative analysis, we analyze the D phase dominating the initial phases. Our analysis for the signals of 0.2-1.0 Hz shows the D phase are well explained by a cylindrical contraction source with a half cosine shaped time function located at 1.0-13 km depth beneath the active vent. We also recognize that some explosions are followed by a prominent tremor that coincides with continuous ash emission (ET). The seismic amplitudes and intensity of the D phase of events in ET are larger than the explosions without accompanying tremor (EX). The frequency distribution of the time interval from the previous eruption is also different in the events in ET and EX. The implosion source in the initial phases of explosion earthquakes at several km beneath the active vent has been reported at Sakurajima volcano. Since our result shows considerable agreement with the previous works at Sakurajima, both Lokon-Empung and Sakurajima may share similar initial processes of Vulcanian eruptions. (C) 2016 Elsevier B.V. All rights reserved.
  • Takeshi Nishimura, Masato Iguchi, Mohammad Hendrasto, Hiroshi Aoyama, Taishi Yamada, Maurizio Ripepe, Riccardo Genco
    EARTH PLANETS AND SPACE 68 125  1880-5981 2016/07 [Refereed][Not invited]
     
    Magnitude-frequency distributions of volcanic explosion earthquakes that are associated with occurrences of vulcanian and strombolian eruptions, or gas burst activity, are examined at six active volcanoes. The magnitude-frequency distribution at Suwanosejima volcano, Japan, shows a power-law distribution, which implies self-similarity in the system, as is often observed in statistical characteristics of tectonic and volcanic earthquakes. On the other hand, the magnitude-frequency distributions at five other volcanoes, Sakurajima and Tokachi-dake in Japan, Semeru and Lokon in Indonesia, and Stromboli in Italy, are well explained by exponential distributions. The statistical features are considered to reflect source size, as characterized by a volcanic conduit or chamber. Earthquake generation processes associated with vulcanian, strombolian and gas burst events are different from those of eruptions ejecting large amounts of pyroclasts, since the magnitude-frequency distribution of the volcanic explosivity index is generally explained by the power law.
  • NAKAMICHI Haruhisa, AOYAMA Hiroshi
    BULLETIN OF THE VOLCANOLOGICAL SOCIETY OF JAPAN 日本火山学会 61 (1) 119 - 154 0453-4360 2016/03 [Refereed][Not invited]
     
    This paper reviews the eruption processes, as well as the processes leading up to the eruption, as revealed by multi-parameter geophysical observations. First, we briefly describe the history and development of geophysical observational methods in Japan. A prototype of multi-parameter geophysical observation had already been established at a few volcanoes in Japan 50 years ago. To obtain high-quality geophysical data, underground tunnels and boreholes had been constructed around volcanoes, and seismometers, tiltmeters, and strainmeters had been installed in them during the 1980s and 1990s. Broadband seismometers and a data logger with a GPS clock that are small and lightweight, were introduced in the mid-1990s. Combined with large data storage capacity in the data loggers and efficient data transmission using IP protocols, simultaneous multi-parameter geophysical observations have been intensively and continuously conducted since the early 2000s in order to reveal the eruption processes. Since then, various analysis methods suitable for multi-parameter observations have been developed. Although the time scales of volcanic eruptions vary widely, from several seconds to several decades, most of these scales are covered by multi-parameter geophysical observation. We review the advances and challenges for understanding not only the eruption processes, but also the precursory processes leading up to eruptions, which have been revealed by multi-parameter geophysical observations during the past decade. The explosive eruption processes, which include Plinian, Vulcanian, and Strombolian eruptions, and effusive eruptions, which include Hawaiian and dome-forming eruptions, are also reviewed. Physical models for these types of eruptions have been developed experimentally and theoretically, and examined later using geophysical observations. For each type of eruption, we briefly introduce the proposed physical models and describe their progress, mainly from the viewpoint of multi-parameter geophysical observations. The eruption processes of Plinian eruptions have been revealed mainly by worldwide seismic and infrasound observation networks and satellite images. Vulcanian and Strombolian eruptions are most intensively studied by multi-parameter geophysical observations, because of their high-frequency nature and accessibility to the proximity of active craters in deploying monitoring instruments. For example, the precursory processes of Vulcanian eruptions are characterized by inflation, relatively stable, and slight deflation stages of the volcano edifices, which are inferred by continuous crustal deformation measurements. Strombolian eruptions are understood as repeating strong gas bursts at the surface of liquid magma. Recently, new monitoring techniques such as high-speed cameras and portable radar units have been introduced to observe the Strombolian surface activities. Hawaiian eruptions are characterized by explosive lava fountains and large lava flows traveling more than several kilometers. Multi-parameter observations are quite useful for monitoring the locations of dike intrusions and lava fountains. Dome-forming eruptions have the longest time-scales among these eruption styles. Temporal fluctuations of dome growth are well monitored by geodetic and photogrammetric observations. Recent seismic observations of dome-forming have revealed the characteristic repeating earthquakes and provided new insights into the physical mechanisms of dome growth. Our understanding of the physical process of phreatic eruptions is quite limited relative to magmatic eruptions. Recently, tilt changes associated with tremors were sometimes observed before phreatic eruptions at several volcanoes, and may be forerunners of phreatic eruptions. We need much more data to understand the processes leading up to phreatic eruptions. Erupted volumes and rates are inferred from multi-parameter geophysical
  • Hiroshi Aoyama, Hiromitsu Oshima
    EARTH PLANETS AND SPACE 67 119  1880-5981 2015/07 [Refereed][Not invited]
     
    Although forecasting an occurrence of phreatic eruption is very difficult, it has been reported that some precursory activities often precede these eruptions at several volcanoes. In this study, we observed seismic activities before and during the 2008 phreatic eruption at Meakan-dake volcano, eastern Hokkaido, Japan, by using broadband seismometers and surface mount-type tiltmeters. The precursory increase in seismicity began in late September about 2 months before the first eruption on November 18. After several rises and falls in seismicity in October and in early November, a small volcanic tremor was observed early on November 16. Although the original velocity seismogram of the tremor generally appeared to be spindle shaped, an outstanding ramp function appeared in the displacement seismogram obtained by simple integration. Since the ramp function appeared only in the horizontal components and continued for about 3 min, which is sufficiently longer than the natural period of the seismometer, we regarded the ramp function as an expression of the tilting motions of seismic stations that was quantitatively confirmed by the strong similarity between horizontal displacement seismograms and tilt data from co-located biaxial tiltmeter. Azimuthal distribution of three tilting vectors obtained from broadband seismograms was not consistent with a simple spherical source but rather strongly suggested a vertical dike under the crater. In this study, we confirmed that an almost vertical single dike effectively explains the observed tilting vectors. The estimated volume increase in the dike was 4-5 x 10(4) m(3). The strike direction of the dike is highly consistent with the alignment of the hydrothermal area on and around the volcano. Our dike model also partially explains the changes in global navigation satellite system (GNSS) measurement and in groundwater levels reported in previous research. Since a similar deformation coincided with a volcanic tremor preceding the 2006 eruption, we interpret that this must be an important preparatory process of phreatic eruptions at Meakan-dake volcano.
  • Takeshi Nishimura, Masato Iguchi, Hiroshi Yakiwara, Jun Oikawa, Ryohei Kawaguchi, Hiroshi Aoyama, Haruhisa Nakamichi, Yusaku Ohta, Takeshi Tameguri
    BULLETIN OF VOLCANOLOGY 75 (12) 779  0258-8900 2013/12 [Refereed][Not invited]
     
    We examine precursory signals of vulcanian eruptions at Suwanosejima volcano, southwest of Japan, by deploying seismic and tilt stations close to the active crater to understand the shallow conduit processes just before explosions. Vulcanian eruptions at Suwanosejima for the period from October 2009 to 2011 are often preceded by a sudden cessation of continuous tremor associated with continuous ash emissions. The amplitude of continuous tremor decreases within about 10 s, and tilt signal starts to show uplift of the active crater. Then, the pause of continuous tremor and uplift continue for about 1-2 min, and tilt amplitudes reach a few tens of nanoradians at a distance of 400 m from the active crater. As the pause time of continuous tremor before explosion becomes longer, the maximum amplitude of explosion earthquake and uplift signal become larger. Vulcanian eruptions are also observed during periods without continuous tremor. In these cases, tilt signals capture uplifts of the active crater for about 10 min before explosions and reach a few tens of nanoradians. Cessations of volcanic gas emissions are observed before some explosions during periods without continuous tremor (Mori et al. 2011). These observations suggest that pressurization in the shallow conduit is caused by an accumulation of volcanic gases and ash through the formation of 'cap' in the conduit, possibly composed of stiffened magma due to degassing, cooling, rheological changes, or other mechanisms.
  • NAKAMICHI HARUHISA, AOYAMA HIROSHI, NISHIMURA TAKESHI, YAKIWARA HIROSHI, OTA YUSAKU, YOKOO AKIHIKO, IGUCHI MASATO
    京都大学防災研究所年報(CD-ROM) 京都大学防災研究所 (56) 227 - 235 0386-412X 2012 [Not refereed][Not invited]
     
    We conducted a small-aperture seismic array observation at Suwanose-jima volcano for the period from 1 October to 18 November 2010. The seismic array consists of 13 elements of short-period seismometers and 5 data loggers. We perform array analysis for continuous seismic records observed during this period to investigate the wave-field properties of several episodes of volcanic tremors and 30 explosion earthquakes. Averages of the slowness values and back azimuths of volcanic tremors are estimated to be 0.8-1.4 s/km and 0°-40°, respectively. This suggests that the tremor wave consists of body and surface waves that propagate from the active crater. The array analyses and particle motions of explosion earthquakes indicate that the initial parts of the waveforms of explosion earthquakes are S waves that come from the direction of the active crater. The slowness values of the S waves of the explosion earthquakes are 0.3-0.5 s/km. Variation of the slowness value reflects the depth change of the explosion sources.
  • TSUTSUI Tomoki, TAMEGURI Takeshi, IGUCHI Masato, OIKAWA Jun, OSHIMA Hiromitsu, MAEKAWA Tokumitsu, AOYAMA Hiroshi, UEKI Sadato, HIRAHARA Satoshi, NOGAMI Kenji, OHMINATO Takao, ICHIHARA Mie, TSUJI Hiroshi, HORIKAWA Shinichiro, OKUDA Takashi, SHIMIZU Hiroshi, MATSUSHIMA Takeshi, OHKURA Takahiro, YOSHIKAWA Shin, SONODA Tadaomi, MIYAMACHI Hiroki, YAKIWARA Hiroshi, HIRANO Shuichiro, SAITO Koichiro, SUEMINE Koichi, GOTO Susumu, IKEGAME Takamitsu, KATO Koji, MATSUSUE Shinichi, KOHNO Taisuke, UTSUNOMIYA Shingo, GOTO Hirohito, WATANABE Ryuichi, MAEHARA Yuki, SATOH Izumi, OYABU Ryudo, SHIMIZU Hidehiko, YAMASHITA Yusuke
    Annuals, Disaster Prevention Research Institute, Kyoto University 京都大学防災研究所 54B (54) 195 - 208 0386-412X 2010 [Not refereed][Not invited]
     
    The second round of the repetitive seismic experiment was carried out on ecember 2010 in Sakurajima Volcano after an inflation period in June. The temporary seismic network was reconstructed well for the 2009's network within 0.1m northward and 0.2m eastward in the average. The data acquisition was successful in 245 of the 248 deployed stations. The amplitude variation ranged within 0.8 to 1.5 times of the 2009's data and the travel time differences were less than 8ms. The reproduction of the waveform was also successful. The residual seismograms were made and include variation of the phase appearance with referring to the 2009's seismogram at the corresponding station. Most of the variations are found around 1.5 to 3 seconds of the residual seismograms.
  • Hiroshi Aoyama, Shin'ya Onizawa, Tomokadu Kobayashi, Takeshi Tameguri, Takeshi Hashimoto, Hiromitsu Oshima, Hitoshi Y. Mori
    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH 187 (3-4) 203 - 217 0377-0273 2009/11 [Refereed][Not invited]
     
    Post-eruptive crustal activity after the 2000 eruption of Usu volcano was investigated by seismic and geodetic field observations. Remarkable features of the magmatic eruptions that occur almost every 30 years include lava dome formation and strong precursory earthquakes. On the other hand, rapid dome subsidence was observed by electronic distance meter (EDM) measurement after the 1977-1982 summit eruption. Since the 2000 eruption, seismic activity at a shallow part under the summit crater has remained at a high level relative to that after the 1977-1982 eruption, although eruption occurred at the western foot of the volcano during the 2000 eruption. To reveal the shallow crustal activity in the inter-eruptive period around the summit area, seismicity and crustal deformation have been investigated since 2006. Dense temporary seismic observations and hypocenter relocation analysis using a three-dimensional velocity structure model revealed that the focal area is localized along the U-shaped fault that developed in the dome-forming stage of the 1977-1982 eruption. Three major focal clusters are distributed on the southwestern side of Usu-Shinzan cryptodome, which was built up during the 1977-1982 eruption. For the seven major events with magnitudes larger than 1, the focal mechanism was a large dip-slip component, which suggests the subsidence of Usu-Shinzan cryptodome. Interferomatetric satellite aperture radar (InSAR) image analysis and repeated GPS measurements revealed subsidence of the summit dome, which is almost centered at the Usu-Shinzan cryptodome. The area of rapid deformation is restricted to a small area around the summit crater. The estimated rate of dome subsidence relative to the crater floor is about 3 cm/year. These results strongly suggest that subsidence of Usu-Shinzan is associated with the small earthquakes along the U-shaped fault that surrounds the cryptodome. According to prior seismic and geodetic studies, it is thought that most of the magma rising under the summit crater during the 2000 eruption stopped around a depth of 2 km below sea level, which is sufficiently deep relative to the focal area of the present seismicity. A part of the magma intruded under the western foot and contributed to the 2000 eruption. We conclude that the 2000 eruption scarcely affected the shallow crustal activity under the summit crater, and that Usu-Shinzan cryptodome is continuing to subside just as it was before the 2000 eruption. The shallow volcanic earthquakes that began increasing from 1995 are closely related to the successive subsidence of the summit domes. Temporal change in fumarole temperature suggests a relationship between the shallow earthquakes and cooling of the magma that intruded under Usu-Shinzan during the 1977-1982 eruption. (c) 2009 Elsevier B.V. All rights reserved.
  • Yosuke Aoki, Minoru Takeo, Hiroshi Aoyama, Jun Fujimatsu, Satoshi Matsumoto, Hiroki Miyamachi, Haruhisa Nakamichi, Takahiro Ohkura, Takao Ohminato, Jun Oikawa, Rie Tanada, Tomoki Tsutsui, Keigo Yamamoto, Mare Yamamoto, Hitoshi Yamasato, Teruo Yamawaki
    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH 187 (3-4) 272 - 277 0377-0273 2009/11 [Refereed][Not invited]
     
    An active seismic survey with unprecedented density of seismometers found a high velocity zone to the west of the summit of Asama Volcano. Japan. The high velocity zone coincides with an area of magma-filled crack (dike) intrusion associated with the 2004 eruptions inferred from precise earthquake relocations and ground deformation modeling. It also coincides with an area of high resistivity surrounded by low resistivity, indicating that the solidification of magma due to repeating intrusions is responsible for the high velocity. This thus endorses the magma pathway previously speculated by seismic and geodetic observations. These findings demonstrate that dense seismic exploration combined with geophysical monitoring is an effective way to understand the dynamics of volcanic eruptions. (c) 2009 Elsevier B.V. All rights reserved.
  • TAKEO Minoru, AOKI Yosuke, OHMINATO Takao, URABE Taku, OIKAWA Jun, TSUJI Hiroshi, KOYAMA Etsuro, OSADA Noboru, OSHIMA Hiromitsu, AOYAMA Hiroshi, MAEKAWA Tokumitsu, SUZUKI Atsuo, TANAKA Satoshi, ISHIHARA Yoshiaki, YAMAMOTO Mare, YAMADA Mamoru, OKURA Takahiro, INOUE Hiroyuki, IGUCHI Masato, TAMEGURI Takeshi, UEHIRA Kenji, NAKAMOTO Masami, HIRANO Shuichiro
    Bulletin of the Earthquake Research Institute, University of Tokyo 84 (1) 1 - 37 0040-8972 2009/07 [Refereed][Not invited]
  • Shin'ya Onizawa, Hiromitsu Oshima, Hiroshi Aoyama, Tokumitsu Maekawa, Atsuo Suzuki, Hiroki Miyamachi, Tomoki Tsutsui, Takeshi Matsushima, Satoru Tanaka, Jun Oikawa, Norimichi Matsuwo, Keigo Yamamoto, Toru Shiga, Takehiko Mori
    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH 183 (3-4) 245 - 253 0377-0273 2009/06 [Refereed][Not invited]
     
    We investigate the basement structure of the Hokkaido Komagatake volcano, Japan, by an artificial seismic survey. By inverting first arrival time data, a three-dimensional P-wave velocity model down to 3 km b.s.l. is obtained. The resultant velocity model reasonably reflects regional geological features and is consistent with Bouguer anomalies. Around the Komagatake volcano, the velocity basement deepens to NNW on the whole, reflecting the deepening of the geological basement toward that direction. Higher velocities are observed in Oshima and Kameda Mountains where Neogene volcanic and sedimentary rocks are present. On the contrary, lower velocities are observed in lowlands surrounding the volcano, where Komagatake deposits and Quaternary sediments crop out. At the volcano, a prominent high velocity zone was detected from the surface down to a depth of 1.5 km b.s.l. Above the base, probably a contrast between the core part with higher proportion of massive lavas and intrusions and flank areas dominated by loose pyroclastic deposits caused the prominent high velocity. Below the base, it is thought that solidified intrusive bodies largely contribute to making the high velocity. Further, a high velocity elongates from Kameda Mountains to beneath the summit. This is due to a shallower of the volcano substratum. (C) 2009 Elsevier B.V. All rights reserved.
  • M. Ichihara, M. Ripepe, A. Goto, H. Oshima, H. Aoyama, M. Iguchi, K. Tanaka, H. Taniguchi
    Journal of Geophysical Research 114 (B3) B03210  0148-0227 2009/03/26 [Refereed][Not invited]
  • OGAWA Tatsunori, SASAKI Hisashi, NOWA Yukinori, AOYAMA Hiroshi
    Journal of the Japan Society of Erosion Control Engineering 公益社団法人 砂防学会 61 (6) 27 - 30 0286-8385 2009/03 [Refereed][Not invited]
  • Hiroshi Aoyama, Hiromitsu Oshima
    GEOPHYSICAL RESEARCH LETTERS 35 (6) L06307  0094-8276 2008/03 [Refereed][Not invited]
     
    [1] We discovered an anomalous very long period (VLP) signal ( duration: about 60 s) in the broadband seismic record of the precursory swarm of a small phreatic explosion at the Meakan-dake volcano, Hokkaido, Japan, in 2006; this signal was masked by a short-period tremor in the original velocity waveform, but a considerable DC step appeared in the displacement trace. Since such a step results from a tilt change, we interpreted the observed trace as being a combination of rotational ( tilt) and translational ( displacement) motions. The apparent displacement step in the VLP signal indicates subsidence of the summit crater. Owing to limited data, we attempted deflating the Mogi source and simulating the seismic record including both motions. When only rotational motion is considered, the simulated waveform explains well the general features of the observed trace. However, the combined trace has incompatible phases, suggesting that a more complicated source process should be considered.
  • H. Aoyama
    Bulletin of Volcanological Society of Japan 日本火山学会 53 (1) 35 - 46 0453-4360 2008/02/28 [Refereed][Not invited]
     
    Deformation under the ground excites not only translational motion but also tilt changes, although seismologists usually analyze recorded waveforms under an assumption that seismogram only expresses translational motion. Since broadband seismometers have high enough sensitivity to tilt changes, the seismograms are sometimes contaminated by tilting motion at a seismic station. To check the effect of tilt change on seismogram recorded by a broadband velocity seismometer, we performed a simple experiment with a CMG40T seismometer and a tilt sensor of surface mount type. Tilt changes yield one-sided oscillation of the pendulums in a horizontal transducer. Such particular oscillation is clearly identified in the displacement trace calculated from the original velocity seismogram. Theoretical consideration predicts that slow temporal changes in tilt angle correlate with a time function of the apparent displacement of seismogram. Since results of our experiment well agree with the prediction, we estimate the conversion coefficient from the apparent displacement to tilt angle and confirm that the coefficient obtained experimentally well corresponds with the value from theoretical prediction. As a possible example in an active volcano, we consider slow isotropic volume change near a seismic station and calculate synthetic seismogram due to the volume change.
  • AOKI Y, TAKEO M, TSUJI H, KOYAMA E, AOYAMA H, FUJIMATSU J, MATSUMOTO S, MIYAMACHI H, NAKAMICHI H, OHKURA T, OHMINATO T, OIKAWA J, TANADA R, TSUTSUI T, YAMAMOTO K, YAMAMOTO M, YAMASATO H, YAMAWAKI T, ICHIHARA M, IMOTO Y, KAZAMA T, KOYAMA T, MAEDA Y, MAENO F, MORITA Y, NAKADA S, NAKAMURA S, OSADA N, WATANABE H, ALANIS P.K.B, ANGGONO T, FUJIWARA Y, FUKUYAMA Y, HAGIWARA S, HASHIMOTO T, HIRANO S, HORIGUCHI K, IIJIMA S, ISHIHARA Y, ISHIKAWA K, ISHIZAKA K, KITAWAKI Y, KUROKI H, KUSANO F, MAEKAWA T, MASUDA Y, MATSUMURA T, NAKAMOTO M, NISHIMURA T, NOGAMI K, OKUDA T, SAKAI T, SATO M, SUZUKI A, TANGE G, UEKI S, WATANABE A, YAKIWARA H, YAMAZAKI Y, YOSHIKAWA S
    Bulletin of the Earthquake Research Institute, University of Tokyo 東京大学地震研究所 83 (1) 1 - 26 0040-8972 2008/01 [Refereed][Not invited]
     
    application/pdf
  • Masayuki Murase, Koji Ono, Takeo Ito, Rikio Miyajima, Hitoshi Mori, Hiroshi Aoyama, Hiromitu Oshima, Yuka Yoshida, Akihiko Terada, Eturo Koyama, Toyotarou Takeda, Hidefumi Watanabe, Fumiaki Kimata, Naoyuki Fujii
    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH 164 (1-2) 54 - 75 0377-0273 2007/07 [Refereed][Not invited]
     
    A time-dependent model for volume changes in pressure sources at Asama volcano is developed from precise leveling data collected since 1902. The optimal source model is determined by comparing five different models (a model with three types of spherical sources, single dike, and dike with a spherical source) during three periods: 1935 to 1939, 1939 to 1950/1953, and 1990 to November 2004. The optimal parameters for each model are estimated by employing a genetic algorithm (GA). The model with two spherical sources was selected as the optimal model. In this model, one of the sources was estimated to be located at a depth of approximately 6 km beneath Kurofu volcano; the other source was estimated to be located close to Maekake volcano at a depth of approximately 2 km. The volume changes in the two spherical sources are calculated using the Akaike's Bayesian information criterion (ABIC) for the period from 1902 to 2005. During the period from 1902 to 1943, a large inflation was estimated in a source at a depth of approximately 6 km beneath Kurofu volcano, which is an older volcano at the base of Asama. After 1943, a rapid deflation continued until 1967. This rapid deflation changed to a marginal inflation that continued from 1967 until 2005. The temporal change in the pressure source beneath Kurofu volcano exhibits a strong positive correlation with the eruption frequency. The leveling data does not suggest a significant volume change in the source beneath Kurofu volcano during the quiet period between 1962 and 2005. During the 20th century, magma appears to have been episodically supplied beneath Asama volcano. In particular, the inflation of the source beneath Kurofu volcano, and probably the magma supply, reached a peak from 1930 to 1940. (c) 2007 Elsevier B.V. All rights reserved.
  • 臨時稠密地震観測で見えてきた有珠山の微小地震活動
    青山 裕, 鬼澤真也, 為栗 健, 鈴木敦生, 前川徳光, 大島弘光, 森 濟, 橋本武志, 志賀 透, 小山 寛, 中橋正樹, 吉川章文, 福山由朗
    北海道大学地球物理学研究報告 70 107 - 121 2007/03 [Not refereed][Not invited]
  • Shin'ya Onizawa, Hiromitsu Oshima, Hiroshi Aoyama, Hitoshi Y. Mori, Tokumitsu Maekawa, Atsuo Suzuki, Tomoki Tsutsui, Norimichi Matsuwo, Jun Oikawa, Takao Ohminato, Keigo Yamamoto, Takehiko Mori, Taka&apos, aki Taira, Hiroki Miyamachi, Hiromu Okada
    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH 160 (1-2) 175 - 194 0377-0273 2007/02 [Refereed][Not invited]
     
    The three-dimensional P-wave velocity structure of Usu volcano, Japan, is investigated by using first arrival time data of the 2001 active seismic survey. The velocity structure down to the Pre-Neogene basement below the volcano is revealed. The most prominent feature of the velocity model is the deepening of the basement toward the south-southwest. The resultant velocity model contributes to the relocations of 2000 eruption precursory earthquakes. The precursory seismic activity, which reflects pre-eruptive magma movements, is divided into three parts: (1) a sub-vertical distribution indicating magma ascent to beneath the summit of the volcano, (2) a northward migration that indicates magma movement resulting in the subsequent eruptions at the northwestern foot, and (3) a horizontal southward migration possibly indicating intrusion of sill. The northward and southward migrating earthquakes are constrained by the dipping basement structure such that most of the events occur within the middle Miocene or Pre-Neogene layer. The geographical distribution of craters and the upheavals of past eruptions are also constrained by the subsurface basement. At the northern foot of Usu Volcano, the distribution of these craters and upheavals is such that they are enclosed by the subsurface basement, which becomes shallower toward the north. On the other hand, no traces of eruptions are found in the southern and southwestern foots where the basement deepens toward the south-southwest. (c) 2006 Elsevier B.V. All rights reserved.
  • Micro-earthquake activity at Usu volcano revealed by temporary dense observation
    Hiroshi Aoyama, Shin'ya Onizawa, Takeshi Tameguri, Atsuo Suzuki, Tokumitsu Maekawa, Hiromitsu Oshima, Hitoshi Mori, Takeshi Hashimoto, Toru Shiga, Hiroshi Koyama, Masaki Nakahashi, Akifumi Yoshikawa, Yoshirou Fukuyama
    Journal of the Hokkaido University, Faculty of Science, Series VII: Geophysics (70) 107 - 121 0441-067X 2007 
    We performed temporary dense observation at Usu volcano in summer 2006, aiming to reveal micro-earthquake activity under the summit crater during dormant period of the volcanic activity. During about 80 days of temporary observation, more than 330 volcanic earthquakes were observed. Of these earthquakes, well-recorded 142 events are selected for relocation analysis assuming the 3D-velocity structure model which is a result of the explosion seismic experiment at Usu volcano in 2001. Following the result of relocation, we estimated focal mechanism of 7 earthquakes whose magnitudes are more than 1.0. The temporal observation and analyses gave us three new insights about seismic activity 1) Continuous activity of volcanic earthquake is seen at the shallow part under the southern crater floor, 2) Hypocentral regions are distributed along the SW end of the U-shaped fault which was built in the 1977-1982 eruption associated with the uplift of Usu-Shinzan crypt dome, 3) Strike direction of the 7 major earthquakes are almost parallel to the U-shaped fault, and dominant mechanism is dip-slip type which suggests subsidence of summit domes relative to the southern crater floor.
  • Watanabe Hidefumi, Nakamichi Haruhisa, Ohminato Takao, Kagiyama Tsuneomi, Oikawa Jun, Aoki Yosuke, Tsuji Hiroshi, Koyama Etsurou, Osada Noboru, Hagiwara Michinori, Takeda Toyotarou, Kobayashi Masakatsu, Oshima Hiromitsu, Aoyama Hiroshi, Maekawa Tokumitsu, Suzuki Atsuo, Tanaka Satoshi, Nishimura Takeshi, Nita Kouichi, Yamazaki Jun, Okuda Takashi, Yamada Mamoru, Okura Takahiro, Sudo Yasuaki, Yoshikawa Shin, Iguchi Masato, Shimizu Hiroshi, Uehira Kenji, Matsushima Ken, Yakiwara Hiroshi, Hirano Shuichiro
    Bulletin of the Earthquake Research Institute,University of Tokyo 地震研究所 82 (3) 195 - 207 0040-8972 2007 [Refereed][Not invited]
     
    A joint dense seismic observation experiment was conducted during the period of September 2002～April 2005 in cooperation of researchers of national universities under the national project for prediction of volcanic eruption. Major objectives include seismic exploration of the subsurface structure of Fuji volcano and surrounding area as well as array observation of deep low frequency earthquakes, the activity of which increased in 2000－2001 beneath the volcano. We installed 28 seismographs temporarily on and around Fuji volcano and the data was transmitted to the Volcano Research Center (VRC), Earthquake Research Institute by satellite, radio and cable telemetry systems. We further collected seismic data of permanent stations around Fuji volcano operated by related research institutions. All the data was collected and picked at VRC. In this initial report we describe the brief outline of the joint experiment, and summarize the preliminary results of analyses on the seismic velocity structure of Fuji volcano and wave characteristics of a low frequency earthquake, which occurred on 11 September 2003.
  • Weak glow at Tarumae volcano, Japan, witnessed by the high-sensitive camera soon after the Tokachi-oki Earthquake in 2003(MJMA 8.0)
    TERADA Akihiko, NAKAGAWA Mitsuhiro, OSHIMA Hiromitsu, AOYAMA Hiroshi, KAMIYAMA Hiroyuki
    Bulletin of the Earthquake Research Institute, University of Tokyo 79 (1/2) 17 - 26 0040-8972 2004/11 [Refereed][Not invited]
  • AOYAMA Hiroshi, OSHIMA Hiromitsu, SUZUKI Atsuo, MAEKAWA Tokumitsu, ONIZAWA Shin'ya
    Geophysical Bulletin of Hokkaido University 北海道大学大学院理学研究科地球惑星科学専攻（地球物理学） 67 (67) 89 - 109 0439-3503 2004/03 [Not refereed][Not invited]
  • AOYAMA Hiroshi, OSHIMA Hiromitsu, SUZUKI Atsuo, MAEKAWA Tokumitsu
    Geophysical Bulletin of Hokkaido University 北海道大学大学院理学研究科地球惑星科学専攻（地球物理学） 67 (67) 111 - 129 0439-3503 2004/03 [Not refereed][Not invited]
  • AOYAMA Hiroshi, OSHIMA Hiromitsu, SUZUKI Atsuo, MAEKAWA Tokumitsu
    Geophysical Bulletin of Hokkaido University 北海道大学大学院理学研究科地球惑星科学専攻（地球物理学） 67 (67) 131 - 136 0439-3503 2004/03 [Not refereed][Not invited]
  • Seismic exploration at Usu volcano with active sources - The outline of the experiment and the first arrival time data -
    ONIZAWA Shin'ya, OSHIMA Hiromitsu, AOYAMA Hiroshi, MORI Hitoshi Y, MAEKAWA Tokumitsu, SUZUKI Atsuo, OKADA Hiromu, TSUTSUI Tomoki, MATSUWO Norimichi, OIKAWA Jun, OHMINATO Takao, YAMAMOTO Keigo, MORI Takehiko, TAIRA Takaaki, MIYAMACHI Hiroki, KOYAMA Junji, YOMOGIDA Kiyoshi, WATANABE Kenji, MATSUBARA Wakana, OKADA Jun, MIYAMURA Jun'ichi, TANIGUCHI Masami, YOSHIKAWA Akifumi, KATOH Kouji, HAMAGUCHI Hiroyuki, TANAKA Satoru, YAMAZAKI Jun, FUJISAWA Hiroatsu, OGAWA Yasuo, NOGAMI Kenji, SAITOH Akira, MIZUHASHI Shoei, WATANABE Hidefumi, KAGIYAMA Tsuneomi, HAGIWARA Michinori, NAKAMICHI Haruhisa, OSADA Noboru, KOYAMA Etsuro, IMOTO Yoshiko, KOBAYASHI Tomokatsu, HIYAMA Youhei, SUGIOKA Manabu, ISHIMINE Yasuhiro, YAMAOKA Kousyun, OKUDA Takashi, KOIKE Katsuhiko, SUZUKI Takayuki, TSURUGA Kayoko, SHIMIZU Hiroshi, MATSUMOTO Satoshi, MATSUMOTO Kaoru, OHKURA Takahiro, SAKO Mikio, YOSHIKAWA Shin, YAKIWARA Hiroshi, HIRANO Shuichiro, HAYASHIMOTO Naoki, TAMEGURI Takeshi
    Bulletin of the Earthquake Research Institute, University of Tokyo 78 (2) 121 - 143 0040-8972 2003/09 [Refereed][Not invited]
  • Terada Akihiko, Okada Hiromu, Itabashi Nobuaki, Kato Koji, Koyama Hiroshi
    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN 特定非営利活動法人 日本火山学会 2003 1 - 1 2003
  • KATSUMATA Kei, WADA Naoto, KASAHARA Minoru, OKAYAMA Muneo, ICHIYANAGI Masayoshi, ISHIKAWA Haruyoshi, TAKADA Masamitsu, CHO Ikuo, UMINO Norihito, OKADA Tomomi, NAKAMURA Ayako, HORI Shuichiro, TACHIBANA Kenji, KONO Toshio, NIDA Koichi, HASHIMOTO Keiichi, ITO Yoshihiro, IGARASHI Toshihiro, NAKAJIMA Junichi, ASANO Yoichi, ITO Aki, UCHIDA Naoki, SODA Yasue, UJIKAWA Hisako, HASEMI Akiko, DEMACHI Tomotsugu, HIRATA Naoshi, URABE Taku, SAKAI Shin'ichi, IDE Satoshi, OGINO Izumi, SETO Norihiko, SAKAI Kaname, HASHIMOTO Shin'ichi, HANEDA Toshio, YAMANAKA Yoshiko, MIURA Katsumi, HAGIWARA Hiroko, KOBAYASHI Masaru, INOUE Yoshihiro, TAGAMI Kiyoko, NAKAGAWA Shigeki, TSUDA Ken'ichi, MATSUBARA Makoto, TADA Taku, AOYAMA Hiroshi, MATSUZAWA Takanori, ZHAO Yanlai, YAMAZAKI Fumihito, YAMADA Mamoru, SASAKI Yoshimi, HIRAMATSU Yoshihiro, SAIGA Atsushi, KOMORI Tetsuya, UMEDA Yasuhiro, ITO Kiyoshi, KOIZUMI Makoto, WADA Hiroo, HIRANO Norio, NISHIDA Ryohei, MATSUSHIMA Takeshi, UEHIRA Kenji, OSHIMA Mitsutaka, HIRANO Shuichiro
    Bulletin of the Earthquake Research Institute, University of Tokyo 東京大学 77 (3) 199 - 223 0040-8972 2003/01 [Refereed][Not invited]
     
    A group of seismologists from eleven universities operated a dense temporary seismic network from July 1999 to July 2001 in and around the Hidaka Collision Zone, Hokkaido, Japan, where the Kurile Island arc and the northeastern Japan arc meet and collide. All waveform data were telemetered by way of a communication satellite and recorded continuously. We obtained seven thousand well-located hypocenters and 351 focal mechanisms. This research forms a part of ""The new Program of the Study and Observation for Earthquake Prediction"" in Japan started after the Hyogoken-nanbu (Kobe) earthquake in 1995.
  • H. aoyama, H. Oshima, T. Maekawa
    Bulletin of Volcanological Society of Japan 特定非営利活動法人日本火山学会 47 (5) 521 - 531 0453-4360 2002/11/29 [Refereed][Not invited]
     
    There was intense acoustic activity associated with the eruption of Mount Usu, which began on March 31, 2000. Repetitive phreatic explosions generated many isolated infrasonic signals, which were observed at plural acoustic stations. During the periods when acoustic activity was high, infrasonic pulses as many as 200 were identified every 10 minutes. Source location of infrasonic signals could be well identified from the records of the low frequency microphone network. Two active craters, Nishiyama and Konpirayama craterlets, are clearly distinguished by sound source determination analysis in spite of their proximity (〜1 km). To investigate temporal change in the acoustic activity from April to June, 2000, we developed a method to detect arrival and amplitude of infrasonic signals automatically. The number of automatically identified infrasonic signals exceeds 1.46 million during three months. It seems that there is a good correlation between acoustic activity and seismic signal amplitude. Patterns of acoustic activity and infrasonic pulse shapes observed at Usu volcano are very similar to those observed at Stromboli volcano, Italy. We named the acoustic activity attended with phreatic explosion which scatters a lot of clods, "mud-pool Strombolian type". Phreatic explosion excites not only infrasonic pulses but also seismic signals observed before the arrival of an infrasonic pulse. Existence of a Rayleigh wave phase with a large amplitude suggests that the seismic wave is excited at a shallow part of the crater.
  • H Aoyama, M Takeo, S Ide
    JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 107 (B8) 2169-9313 2002/08 [Refereed][Not invited]
     
    [1] An earthquake swarm occurred under the Hida Mountains in central Japan in 1998. The focal area, which expanded from south to north, was distributed above the low-velocity and high-attenuation zone, which lies under the main range. During the swarm, there was a migration of focal areas with time delays. In this paper, we investigate the spatiotemporal distribution of earthquakes in the swarm and discuss the phenomenon that must have controlled the seismicity. Understanding the complicated spatial pattern of seismicity, we investigate the dependency of the occurrence of earthquakes on the static stress changes caused by preceding earthquakes. Our findings show that, for each of 18 major earthquakes (magnitudes 4.0 or higher), the estimated distribution of the resulting Coulomb failure stress corresponds to the expansion of focal areas and the distribution of the seismically quiescent region. However, the detailed structure of seismicity cannot be explained only by the static stress changes. We discuss two additional factors which may control delayed fractures: flow of underground water for the seismicity around the southernmost focal cluster and stress corrosion process for the leaps of seismicities. The results of this study suggest that the 1998 Hida swarm was strongly affected by the disturbances of a static stress field that was created by the swarm itself, although the magnitudes of static stress change are small. The seismic activity was initiated by swarm-type seismicity around the southernmost cluster and then expanded northward gradually due to the increase in static stress.
  • 2001年有珠火山人工地震探査--3次元P波速度構造--
    鬼澤真也, 大島弘光, 青山 裕, 森 済, 前川徳光, 鈴木敦生, 筒井智樹, 松尾のり道, 及川 純, 大湊隆雄, 山本圭吾, 森 健彦, 平 貴昭, 宮町 宏樹, 岡田 弘
    月刊地球 39 14 - 21 0387-3498 2002 [Not refereed][Not invited]
  • H. Aoyama, M. Takeo
    Journal of Volcanology and Geothermal Research 105 (1-2) 163 - 182 0377-0273 2001/01 [Refereed][Not invited]
     
    N-type earthquakes sometimes occur before the eruption of andesitic volcanoes, but their source mechanism has not been understood well. Their waveforms have stationary periods and decay slowly resembling to damped oscillation. They have common characteristics of spectra among the different stations these spectral peaks appear at almost equal intervals of 1.0 Hz with common sharpness. We made detailed analysis on the N-type earthquakes observed at Asama volcano in July 1995. During 10 days activity, the duration of each earthquake increased gradually from 40 s to 3 min, while the peak frequency decreased from 2.7 to 0.8 Hz. Hypocenters are distributed slightly west under the summit crater with 0.4-1.7 km above sea-level. Source mechanism of the N-type earthquake is determined using a waveform inversion technique. Synthetic waveforms are calculated using 2D finite difference method. Surface topography is included in the calculation to incorporate the case that the source region is higher than the stations. Since the optimum solution has a large volumetric component, we approximated the volumetric part as a volume change of fluid filled sphere or cylinder or plane crack, and decomposed the solution into volumetric and non-volumetric part. Consequently, it is revealed that the optimum solution can be expressed as "crack expansion (contraction) + small fault slip", because the spectral peak distribution advocates the crack expansion model among these three candidates. The frequency change during this activity may be explained by the time variation of the sound speed of inner fluid from 300 to 100 m/s. The change of the void fraction of water-steam phase might have caused the decrease of the sound speed. © 2001 Elsevier Science B.V. All rights reserved.
  • 青山 裕, 武尾 実, 渡辺秀文
    火山 45 (6) 323 - 329 2000/12/22 [Refereed][Not invited]
  • Oshima H., Mori H., Maekawa T., Yoshida K., Tamura S., Ichiyanagi M., Okada Hm., Hamaguchi H., Nishimura T., Aoyama H., Tsuji H., Uehira K., Miyamachi H., Yakihara H., Sudo Y., Takayama T.
    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN 特定非営利活動法人 日本火山学会 2000 33 - 33 2000
  • 1995 Explosion Experiment in Unzen Volcano
    MATSUSHIMA Takeshi, SHIMIZU Hiroshi, NISHIMURA Yuichi, UEKI Sadato, NISHIMURA Takeshi, AOKI Shigeki, HAYAKAWA Toshihiko, KAGIYAMA Tsuneomi, MIKADA Hitoshi, OIKAWA Jun, KITAMURA Takehiko, MUNEKANE Hiroshi, WATANABE Tohru, KUMAGAI Hiroyuki, TSUTSUI Tomoki, NISHI Kiyoshi, IGUCHI Masato, MIYAMACHI Hiroki, TAKAGI Akimichi, OKADA Hiromu, MAEKAWA Tokumitsu, AOYAMA Hiroshi, HOSHINO Makoto, OKU Yoshiaki, TAMEGURI Takeshi, MORITA Yuichi, HASHIMOTO Keiichi, NAKAMICHI Haruhisa, SATO Minemori, HIRABAYASHI Jun-ichi, OHBA Takeshi, NOGAMI Kenji, IDA Yoshiaki, WATANABE Hidefumi, YAMASHINA Ken'ichiro, SAWADA Munehisa, GYODA Noriya, MATSUMOTO Tokiko, MASUTANI Fumio, OSADA Noboru, TSUJI Hiroshi, IIDAKA Takashi, TAKEDA Tetsuya, ITO Takeshi, ITO Wataru, NOTSU Kenji, MORI TOshiya, TOMATSU Toshitaka, MASUYAMA Takayuki, YAMAOKA Koshun, OKUDA Takashi, NISHIHARA Masahito, HASADA Yoko, MAEDA Mitoshi, OHTA Kazuya, MATSUWO Norimichi, UMAKOSHI Kodo, FUKUI Risaku, UCHIDA Kazunari, YAKIWARA Hiroshi, OKAAMTSU Norikazu, FUJII Yushiro, MORI Takehiko, MATSUMOTO Yoshihiro, NAKABOH Makoto, YOSHIKAWA Shin, ISHIHARA KAzuhiro, TAKAYAMA Tetsuro, HENDRASTO Muhamad, RATDOMOPURBO Antonius, HIRANO SHuichirou, HIRAMATSU Hideyuki, NAGAOKA Osamu, MATSUSHIMA Masaya, AOKI Tsuneo, MAENAKA Nobuo, TORISU Keita, OGATA Makoto, MATUSUE Shin-ichi, FUKUDA Nobuo, YAMASHITA Takatsugu, IIJIMA Sei, MORI Hirokazu
    Bulletin of the Earthquake Research Institute, University of Tokyo 72 (2/4) 167 - 183 0040-8972 1997 [Refereed][Not invited]

MISC

  • 柘植鮎太, 青山裕, 秋田藤夫, 加藤和彦  日本火山学会講演予稿集  2022-  2022
  • 道東屈斜路カルデラ地域における精密重力モニタリング（2020年〜2021年）
    名和一成, 山崎 雅, 宮川歩夢, 高橋浩晃, 大園真子, 青山 裕, 岡田和見, 山口照寛, 岡 大輔, 岡崎紀俊, 今西祐一, 西山竜一, 本多 亮, 池田 博, 白川龍生, 大井拓磨  日本測地学会第136回講演会要旨集  2021/11
  • 若林環, 風間卓仁, 大柳諒, 岡田和見, 青山裕, 高橋浩晃, 田村良明, 今西祐一, 西山竜一, 福田洋一, 吉川慎, 大倉敬宏, 山本圭吾  日本測地学会講演会要旨  136th-  2021/11
  • 山田大志, 寺田暁彦, 神田径, 上田英樹, 青山裕, 大倉敬宏, 小川康雄, 棚田俊收  日本火山学会講演予稿集  2021-  2021/10
  • ボアホールカメラを用いたしかべ間歇泉の井戸内観測
    柘植鮎太, 青山 裕, 秋田藤夫, 加藤和彦  日本火山学会2021年秋季大会講演予稿集  2021/10
  • 2021年3月有珠山直下やや深部の地震増加イベント
    不破智志, 宮村淳一, 奥山 哲, 青山 裕  日本火山学会2021年秋季大会講演予稿集  2021/10
  • 十勝岳における微小傾斜変動イベントの概要と有限要素法を用いた予備的検討
    近内雪乃, 青山 裕  日本火山学会2021年秋季大会講演予稿集  2021/10
  • 高粘性マグマの水平移動過程解明のための二次元アナログモデル実験
    吉田秀臣, 田中 良, 青山 裕  日本火山学会2021年秋季大会講演予稿集  2021/10
  • Y. Nakashima,, Nishimura T., Aoyama H., Iguchi M., Kanda W., Ohminato T.  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2021-  163  -163  2021/10
  • 竹尾明子, 西田究, 石瀬素子, 青山裕, 青木陽介  日本地震学会秋季大会講演予稿集(CD-ROM)  2021-  2021/10
  • Theodorus Permana, Hiroshi Aoyama  日本地球惑星科学連合大会予稿集(Web) 2021  2021/05  [Not invited]
  • 柘植鮎太, 青山 裕  日本地球惑星科学連合大会予稿集(Web) 2021  2021/05  [Not invited]
  • Ikeda Wataru, Ichihara Mie, Honda Ryo, Aoyama Hiroshi, Sakai Shinichi, Yoshimoto Mitsuhiro  Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research  2020-  137  -137  2020/11
  • 橋本武志, 青山裕, 田中良, 大倉敬宏, 森俊哉  日本火山学会講演予稿集  2020-  2020/10
  • 竹尾明子, 石瀬素子, 西田 究, 青山 裕, 青木陽介  日本地球惑星科学連合大会予稿集(Web) 2020  2020/05  [Not invited]
  • 池田 航, 市原美恵, 本多 亮, 青山 裕, 酒井慎一  日本地球惑星科学連合大会予稿集(Web) 2020  2020/05  [Not invited]
  • 手嶌典子, 西村太志, 青山 裕, 柘植鮎太  日本地球惑星科学連合大会予稿集(Web) 2020  2020/05
  • 柘植鮎太, 青山 裕, 一柳昌義  日本地球惑星科学連合大会予稿集(Web) 2020  2020/05  [Not refereed][Not invited]
  • 寺田暁彦, 香取慧, 谷口無我, 山本希, 山田大志, 鬼澤真也, 西澤達治, 青山裕, 森田裕一, 大場武  日本地球惑星科学連合大会予稿集(Web)  2020-  2020/05
  • 小川 康雄, 青山 裕, 山本 希, 筒井 智樹, 寺田 暁彦, 大倉 敬宏, 神田 径, 小山 崇夫, 金子 隆之, 大湊 隆雄, 石崎泰男, 吉本 充宏, 石峯 康浩, 野上 健治, 森 俊哉, 木川田 喜一, 片岡 香子, 松元 高峰, 上石 勲, 山口 悟, 伊藤 陽一, 常松 佳恵  自然災害科学総合シンポジウム講演論文集  (56)  1  -5  2019/09/11  [Not refereed][Not invited]
     
    2019年9月11日(水), 於 : キャンパスプラザ京都 第1講義室草津白根山では, 近年の火山活動が湯釜火口周辺に限定されていた。2014年からは, 湯釜火口周辺で活動が高まり, 山体の膨張を伴う地震活動, 熱活動, 火山ガス成分の変化が観測され, 2年後には活動が終息した。一方で, 1500年間活動のなかった本白根山鏡池北火口で, 2018年1月23日に顕著な前駆的活動を伴わない水蒸気噴火が発生し, 人的な被害が生じた。この噴火を受けて2018年度, 2019年度に, 地震学・測地学・地球電磁気学・地球化学・地質学に渡る科研費研究が実施された。噴火に先立って前兆的な現象の有無について, それぞれの分野で検討がなされた。また水蒸気噴火後にマグマ噴火への移行の可能性もありモニタリング研究を継続したが, 現状では, 本白根火山鏡池北火口の再活動の兆しは見当たらない。一方, 草津白根山湯釜火口付近は, 2018年4月, 同9月, 2019年5月に傾斜変動を伴う地震活動が発生し, 再び活動的になってきている。
  • 高橋 浩晃, 勝俣 啓, 大園 真子, 橋本 武志, 青山 裕, 酒井 慎一, 松本 聡, 岡田 知己, 小菅 正裕, 寺川 寿子, 飯尾 能久, 中尾 茂, 上嶋 誠, 柴田 智郎, 大津 直, 高井 伸雄, 飯場 正紀, 渡部 要一, 菊地 優, 岡崎 太一郎, 白井 和貴, 西村 裕一, 石川 達也, 高瀬 裕也, 永井 宏, 宮森 保紀, 三宅 弘恵, 松島 信一, 浅野 公之, 重藤 迪子, 卜部 厚志, 前田 宜浩, 石澤 友浩, 廣瀬 亘, 小山内 信智, 山田 孝, 笠井 美青, 檜垣 大助, 風間 基樹, 千木良 雅弘, 渦岡 良介, 竹林 洋史, 木村 誇, 石丸 聡, 岡田 成幸, 内田 賢悦, 有村 幹治, 植松 武是, 多々納 裕一, 梶谷 義雄, 能島 暢呂, 田村 圭子, 中村 洋光, 戸松 誠  自然災害科学総合シンポジウム講演論文集  56-  (56)  21  -26  2019/09/11  [Not refereed][Not invited]
     
    2019年9月11日(水), 於 : キャンパスプラザ京都 第1講義室「平成30年北海道胆振東部地震」とその災害に関する総合調査を実施した。震度７を記録した揺れにより, 同時多発斜面災害と, 北海道全域同時停電(ブラックアウト)が発生し, 複合的な災害となった。震源の深さは約37kmで, 大すべり域はそれより浅い20-25km付近であった。木造家屋の倒壊が多発したむかわ町市街では, 地盤構造による地震波の増幅が見られた。同時多発斜面崩壊は, 近隣の活火山の噴火による降下火砕堆積物が素因となった。札幌市内の地盤液状化地帯では, 極めて軟弱な谷埋盛土層が確認された。地震発生が未明であったことが, 建物倒壊による直接死が出なかったことに関係している可能性がある。ブラックアウトは, 社会経済活動に大きな影響を与えた。
  • 山田大志, 黒川愛香, 寺田暁彦, 神田径, 上田英樹, 青山裕, 大倉敬宏, 小川康雄, 棚田俊收  日本火山学会講演予稿集  2019-  2019
  • 椎名高裕, 勝俣啓, 一柳昌義, 高橋浩晃, 中村亮一, 加藤愛太郎, 大園真子, 青山裕, 田中良, 高田真秀, 山口照寛, 岡田和見, 酒井慎一, 松本聡, 岡田知己, 松澤暢, 平野舟一郎, 寺川寿子, 堀川信一郎, 小菅正裕, 片尾浩, 飯尾能久, 長岡愛理, 津村紀子, 上野友岳  日本地震学会秋季大会講演予稿集(CD-ROM)  2019-  2019
  • 薄田悠樹, 勝俣啓, 一柳昌義, 大園真子, 青山裕, 田中良, 高田真秀, 山口照寛, 岡田和見, 高橋浩晃, 酒井慎一, 松本聡, 岡田知己, 松澤暢, 平野舟一郎, 寺川寿子, 堀川信一郎, 小菅正弘, 片尾浩, 飯尾能久, 長岡愛理, 津村紀子, 上野友岳  日本地震学会秋季大会講演予稿集(CD-ROM)  2019-  2019
  • 青山裕, 橋本武志, 田中良, 大島弘光, 齋藤公一滝, 道下剛史, 奥山哲  日本地球惑星科学連合大会予稿集(Web)  2019-  2019
  • 竹井 瑠一, 筒井 智樹, 多田 悠也, 森脇 知哉, 青木 陽介, 青山 裕, 丸山 豪  公益社団法人物理探査学会学術講演会講演論文集 = Proceedings of the SEGJ Conference  141-  201  -204  2019  [Not refereed][Not invited]
  • 小川 康雄, 青山 裕, 山本 希, 筒井 智樹, 寺田 暁彦, 大倉 敬宏, 神田 径, 小山 崇夫, 金子 隆之, 大湊 隆雄, 石崎 泰男, 吉本 充宏, 石峯 康浩, 野上 健治, 森 俊哉, 木川田 喜一, 片岡 香子, 松元 高峰, 上石 勲, 山口 悟, 伊藤 陽一, 常松 佳恵  自然災害科学総合シンポジウム講演論文集  (55)  25  -30  2018/09/18  [Not refereed][Not invited]
     
    平成30年9月18日(火), 於 : 京都大学宇治おうばくプラザきはだホール2018年1月23日10時02分に草津白根山を構成する3山体(白根山・逢ノ峰・本白根山)の一つである本白根山鏡池北火口で1500年ぶりの噴火が発生し, 噴石により人的な被害が発生した。この噴火は顕著な前駆的活動を伴わない水蒸気噴火であった。近年の草津白根火山では, 白根山湯釜水釜火口を中心とする水蒸気噴火活動が顕著で, 火山観測は白根山に集中している。一方で, 今回噴火した本白根山では, これまでの最新の噴火が鏡池北火口での1500年前のマグマ噴火であって, 近年, 鏡池北火口付近には顕著な地熱活動は記録されていない。今回の突発的な噴火を受けて, 以下の3点を明らかにするために総合調査を行った。(1)顕著な前駆的な活動がない水蒸気噴火プロセスの解明(2)今後の火山活動の推移の予測, 特にマグマが噴出する可能性の予測(3)融雪泥流発生リスクの評価。これらの研究のために, 地震観測, 地盤変動観測, 熱観測, 噴出物観測, 地球化学観測, 融雪泥流評価を実施した。これまでの研究成果について報告する。
  • MIYAMACHI Hiroki, TAKAHASHI Hiroaki, AOYAMA Hiroshi, SHIINA Takahiro, TAKADA Masamitsu, ICHIYANAGI Masayoshi, YAMAGUCHI Teruhiro, ONO Natsuki, KAZUMA Saito, ITO Chihiro, MURAI Yoshio, TSUTSUI Tomoki, YUSUKE Inoue, TAKEI Ryuichi, YAMAMOTO Mare, HIRAHARA Satoshi, NAKAYAMA Takashi, HINO Ryota, AZUMA Ryosuke, OTOMO Shuhei, KURASHIMO Eiji, IWASAKI Takaya, SHINOHARA Masanao, YAMADA Tomoaki, ABE Eiji, NAKAHIGASHI Kazuo, WATANABE Toshiki, MAEDA Yuta, HORIKAWA Shinichiro, OKUDA Takashi, TSUJI Shuhei, HASEGAWA Daima, KATAO Hiroshi, SHIBUTANI Takuo, MIURA Tsutomu, NAKAGAWA Jun, KATO Shinya, YAMASHITA Yusuke, MATSUSHIMA Takeshi, ISODA Kenshin, TRIAHADINI Agnis, TEGURI Yoshiko, MIYAMACHI Rintaro, SHIMIZU Hiroshi, KOBAYASHI Reiji, NAKAI Kazuho, SODA Masakazu, YAKIWARA Hiroshi, HIRANO Shuichiro  日本地球惑星科学連合大会予稿集(Web)  2018-  ROMBUNNO.SSS11‐10 (WEB ONLY)  2018/05  [Not refereed][Not invited]
  • 山本希, 青山裕, 筒井智樹, 寺田暁彦, 神田径, 小川康雄  日本地球惑星科学連合大会予稿集(Web)  2018-  ROMBUNNO.SVC41‐P10 (WEB ONLY)  2018  [Not refereed][Not invited]
  • 寺田暁彦, 神田径, 小川康雄, 青山裕, 山本希, 筒井智樹, 大倉敬宏, 野口里奈  日本地球惑星科学連合大会予稿集(Web)  2018-  ROMBUNNO.SVC41‐37 (WEB ONLY)  2018  [Not refereed][Not invited]
  • Miyamachi H., Ito C., Murai Y., Tsutsui T., Inoue Y., Takei R., Yamamoto M., Hirahara S., Nakayama T., Azuma R., Otomo S., Takahashi H., Hino R., Abe E., Kurashimo E., Iwasaki T., Shinohara M., Yamada T., Nakahigashi K., Watanabe T., Maeda Y., Horikawa S., Aoyama H., Okuda T., Tsuji S., Hasegawa D., Katao H., Shibutani T., Miura T., Nakagawa J., Kato S., Yamashita Y., Matsushima T., Shiina T., Teguri Y., Miyamachi R., Triahadini A., Isoda K., Shimizu H., Kobayashi R., Soda M., Nakai K., Yakiwara H., Hirano S., Takada M., Tanaka Y., Kawasaki S., Sato N., Ichiyanagi M., Yamaguchi T., Ono N., Saito K.  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2018-  (0)  105  -105  2018  [Not refereed][Not invited]
  • Miyamachi H., Ito C., Murai Y., Tsutsui T., Inoue Y., Takei R., Yamamoto M., Hirahara S., Nakayama T., Azuma R., Otomo S., Takahashi H., Hino R., Abe E., Kurashimo E., Iwasaki T., Shinohara M., Yamada T., Nakahigashi K., Watanabe T., Maeda Y., Horikawa S., Aoyama H., Okuda T., Tsuji S., Hasegawa D., Katao H., Shibutani T., Miura T., Nakagawa J., Kato S., Yamashita Y., Matsushima T., Shiina T., Teguri Y., Miyamachi R., Triahadini A., Isoda K., Shimizu H., Kobayashi R., Soda M., Nakai K., Yakiwara H., Hirano S., Takada M., Tanaka Y., Kawasaki S., Sato N., Ichiyanagi M., Yamaguchi T., Ono N., Saito K.  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2018-  (0)  105  -105  2018  [Not refereed][Not invited]
  • Takeshi Nishimura, Masato Iguchi, Mohammad Hendrasto, Hiroshi Aoyama, Taishi Yamada, Maurizio Ripepe, Riccardo Genco  EARTH PLANETS AND SPACE  69-  2017/10  [Not refereed][Not invited]
  • 山河和也, 石井杏佳, 市原美恵, 青山裕, 西村太志  日本火山学会講演予稿集  2017/09
  • Nakamichi Haruhisa, Aoyama Hiroshi  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2017-  (0)  4  -4  2017  [Not refereed][Not invited]
  • 筒井智樹, 井口正人, 中道治久, 為栗健, 大島弘光, 青山裕, 山本希, 野上健治, 大湊隆雄, 前田裕太, 大倉敬宏, 清水洋, 松島健, 八木原寛, 宮町宏樹, 小林励司, 平原聡, 辻浩, 渡邊篤志, 堀川信一郎, 園田忠臣, 吉川慎, 竹中悠亮, 平野舟一郎, 柳澤宏彰, 菅井明, 井手和彦, 長山泰淳, 滿永大輔, 小窪則夫, 重信有三, 渡辺茂, 畠山康憲  日本地球惑星科学連合大会予稿集(Web)  2017-  ROMBUNNO.SVC47‐23 (WEB ONLY)  2017  [Not refereed][Not invited]
  • 高橋浩晃, 大園真子, 青山裕, 宮町宏樹, 松島健, 山下裕亮, GORDEEV E, MURAVYEV Y, SEROVETNIKOV S  日本測地学会講演会要旨  126th-  149‐150  2016/10/19  [Not refereed][Not invited]
  • Aoyama Hiroshi, Yamada Taishi, Nishimura Takeshi, Kawaguchi Ryohei, Miwa Takahiro, Fujita Eisuke, Ripepe Maurizio, Genco Riccardo  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2016-  164  -164  2016
  • Sugimura Shunsuke, Nishimura Takeshi, Aoyama Hiroshi, Yamada Taishi, Fujita Eisuke, Miwa Takahiro, Kawaguchi Ryohei, Ripepe Maurizio, Genco Riccardo, Valade Sebastien  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2016-  165  -165  2016
  • Kawaguchi R., Nishimura T., Aoyama H., Yamada T., Miwa T., Fujita E., Ripepe M., Genco R., Lacanna G.  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2016-  166  -166  2016
  • 大園真子, 高橋浩晃, 青山裕, 宮町宏樹, 松島健, 山下裕亮, GORDEEV E, YAROSRAV M, SEROVETNIKOV S  日本火山学会講演予稿集  2016-  30  2016  [Not refereed][Not invited]
  • 山本希, 三浦哲, 市來雅啓, 青山裕, 筒井智樹, 江本賢太郎, 平原聡, 中山貴史, 鳥本達矢, 大湊隆雄, 渡邉篤志, 安藤美和子, 前田裕太, 松島健, 中元真美, 宮町凛太郎, 大倉敬宏, 吉川慎, 宮町宏樹, 柳澤宏彰, 長門信也  日本地球惑星科学連合大会予稿集(Web)  2016-  ROMBUNNO.SVC47‐21 (WEB ONLY)  2016  [Not refereed][Not invited]
  • 筒井智樹, 為栗健, 井口正人, 中道治久, 大島弘光, 青山裕, 植木貞人, 山本希, 野上健治, 武尾実, 大湊隆雄, 市原美恵, 及川純, 小山崇夫, 前田裕太, 大倉敬宏, 清水洋, 松島健, 宮町宏樹, 小林励司, 八木原寛  日本地球惑星科学連合大会予稿集(Web)  2016-  ROMBUNNO.SVC47‐09 (WEB ONLY)  2016  [Not refereed][Not invited]
  • Sugimura Shunsuke, Nishimura Takeshi, Aoyama Hiroshi, Yamada Taishi, Fujita Eishuke, Kawaguchi Ryohei, Miwa Takahiro, Ripepe Maurizio, Genco Riccardo  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2015-  138  -138  2015
  • Kawaguchi R., Nishimura T., Aoyama H., Yamada T., Miwa T., Fujita E., Ripepe M., Genco R., Lacanna G  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2015-  131  -131  2015
  • Aoyama H., Hashimoto T., Nishimura T., Ichiki M., Koyama T., Okada K., Tanaka R., Yamada T., Ounaga R., Mishima W.  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2015-  64  -64  2015
  • Kawaguchi R., Nishimura T., Aoyama H., Yamada T., Fujita E., Miwa T., Genco Riccardo, Lacanna Giorgio, Ripepe Maurizio  Programme and abstracts the Volcanological Society of Japan  2014-  60  -60  2014/11/02
  • Characteristics of magnitude-frequency distributions of eruption earthquakes associated with Vulcanian and Strombolian explosions
    Nishimura, T, Iguchi, M, Hendrasto, M, Aoyama, H  Abstracts of Cities on Volcanoes 8  2014/09  [Not refereed][Not invited]
  • Waveform analysis of explosion earthquake at Lokon-Empung volcano and comparative study of dilatational phase of Vulcanian eruption
    Yamada, T, Aoyama, H, Nishimura, T, Yakiwara, H, Nakamichi, H, Oikawa, J, Iguchi, M, Hendrasto, M, Suparman, Y  Abstracts of Cities on Volcanoes 8  2014/09  [Not refereed][Not invited]
  • AOYAMA HIROSHI, MORI HITOSHI, HASHIMOTO TAKESHI, OSHIMA HIROMITSU, MURAKAMI MAKOTO  日本火山学会講演予稿集  2014-  52  -52  2014  [Not refereed][Not invited]
  • AOYAMA HIROSHI, HASHIMOTO TAKESHI, MORI HITOSHI, OSHIMA HIROMITSU, MURAKAMI MAKOTO, USUI YUJI, MIYAMOTO MASASHI  日本火山学会講演予稿集  2013-  33  -33  2013  [Not refereed][Not invited]
  • Yamada T., Aoyama H., Nishimura T., Yakiwara H., Nakamichi H., Iguchi M., Oikawa J., Hendrasto Muhamad, Suparman Yasa  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2013-  (0)  21  -21  2013  [Not refereed][Not invited]
  • Takahashi H., Aoyama H., Nakagawa M., Matsushima T., Miyamachi H., Gordeev E., Muravyev Y., Serovetnikov S.  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2013-  22  -22  2013  [Not refereed][Not invited]
  • Source process of explosive eruptions inferred from a seismic array close to the active crater of Suwanosejima volcano, Japan
    Nakamichi, H, Aoyama, H, Nishimura, T, Yakiwara, H, Ohta, Y, Yokoo, A, Iguchi, M  AGU Fall meeting 2012  2012/12  [Not refereed][Not invited]
  • Hirai Y., Nishimura T., Iguchi M., Tameguri T., Oikawa J., Yakiwara H., Nakamichi H., Aoyama H.  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2012-  (0)  105  -105  2012  [Not refereed][Not invited]
  • Tsutsui T., Oikawa J., Ichihara M., Takeo M., Nakamichi H., Ohkura T., Shimizu H., Matsushima T., Miyamachi H., Yakiwara H., Ueda Y., Iguchi M., Saito K., Sugai A., Tameguri T., Oshima H., Aoyama H., Ueki S., Yamamoto M., Nogami K., Ohminato T.  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2012-  (0)  32  -32  2012  [Not refereed][Not invited]
  • Matsushima T., Takahashi H., Aoyama H., Nakagawa M., Miyamachi H., Goto A., Sergey Serovetnikov, Yaroslav Muravyev, Evgeny Gordeev  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2012-  106  -106  2012  [Not refereed][Not invited]
  • AOYAMA Hiroshi  Bulletin of the Volcanological Society of Japan  56-  (6)  221  -221  2011/12/31
  • Volcano inflations prior to small vulcanian eruptions at Suwanose-jima volcano, Japan
    Nishimura, T, Iguchi, M, Oikawa, J, Yakiwara, H, Aoyama, H, Ohta, Y, Nakamichi, H, Tameguri, T  AGU Fall meeting 2011  2011/12  [Not refereed][Not invited]
  • Yamawaki Teruo, Aoyama Hiroshi, Terada Akihiko, Nogami Kenji  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2011-  137  -137  2011
  • TERADA Akihiko, AOYAMA Hiroshi, NOGAMI Kenji, YAMAWAKI Teruo, SAITO Masaki  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2011-  44  -44  2011
  • OSHIMA H., Aoyama H., Matsumoto S., Shimizu H., Tsutsui T.  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2011-  (0)  143  -143  2011  [Not refereed][Not invited]
  • Nakamichi H., Aoyama H., Nishimura T., Yakiwara H., Ohta Y., Yokoo A., Iguchi M.  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2011-  (0)  106  -106  2011  [Not refereed][Not invited]
  • 一岡 祐生, 梅原 宏之, 大島 弘光, 橋本 武志, 青山 裕  日本火山学会講演予稿集  2010-  2010/10/09  [Not refereed][Not invited]
  • AOYAMA Hiroshi, NAKAJIMA Atsushi, SAITO Yu・ IWAMI, SAITO Yu・ IWAMI, SAITO Yu・ IWAMI, SAITO Yu・ IWAMI  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2010-  104  -104  2010
  • Tsuchiya Ryohei, Aoyama Hiroshi, Hashimoto Takeshi, Mori Hitoshi, Oshima Hiromitsu, Suzuki Atsuo, Matoba Atsushi, Ozaki Takeshi  Programme and abstracts the Volcanological Society of Japan  2009-  2009/10/10  [Not refereed][Not invited]
  • AOYAMA Hiroshi, OSHIMA Hiromitsu  Programme and abstracts the Volcanological Society of Japan  2009-  104  -104  2009/10/10  [Not refereed][Not invited]
  • TERADA AKIHIKO, KAGIYAMA TSUNEOMI, YOSHIKAWA SHIN, YOSHIKAWA AKIFUMI, KOYAMA HIROSHI, YAMAZAKI NOBUYUKI, HIRAMATSU HIDEYUKI, OSHIMA HIROMITSU  北海道大学地球物理学研究報告  (72)  125  -138  2009/03/15  [Not refereed][Not invited]
     
    We developed a new technique, Ice Box Calorimetry, for estimating heat discharge rates through steaming ground. Ice within an aluminum box provides a powerful tool for measuring the total heat transfer from the ground surface, including conductive heat, convective heat, and latent heat within vapor. Using this method, we are able to rapidly measure heat discharge rates without the need for specialized apparatus. Applying Ice Box Calorimetry to the Nishiyama steaming ground at Usu volcano, Japan in September 2006, we identified local variations in heat discharge rates. The total heat discharged from the steaming ground in September 2006 is estimated to be 16 MW.
  • TERADA AKIHIKO, KAGIYAMA TSUNEOMI, MATSUSHIMA NOBUO, YOSHIKAWA SHIN, YOSHIKAWA AKIFUMI, KOYAMA HIROSHI, YAMAZAKI NOBUYUKI, HIRAMATSU HIDEYUKI, OSHIMA HIROMITSU  北海道大学地球物理学研究報告  (72)  139  -157  2009/03/15  [Not refereed][Not invited]
     
    We estimate heat-discharge rates for a geothermal area formed during the 2000 eruption of Usu volcano, Japan. Field observations carried out in September 2006 reveal that heat-discharge rates from fumaroles, areas of steaming grounds and crater lakes are 8, 9.2, and 2 MW, respectively. The total heat-discharge rate measured in September 2006 represents just 1% of the rate immediately following the eruption. Integration of the heat-discharge rate from April 2000 to September 2006 yields an accumulated discharge of approximately 2.3 × 10^[16]J, equating to the cooling of 8 × 10^6 m^3 of magma. This amount of magma corresponds to several percent of the total intruded magma volume estimated from analyses of ground deformation associated with the 2000 eruption. Compared with the 1977 eruption, the 2000 eruption involved the discharge of large amounts of heat from fumaroles. Fumaroles that developed during the 2000 eruption showed a decline in activity in short time. Areas of steaming ground associated with the 2000 eruption showed more rapid growth compared with those of the 1977 eruption but discharged less heat. We suspect that differences in the hydrological environments of the two eruptions (e.g., permeability around the intruded magmas) led to contrasting patterns of propagation of the hydrothermal systems around the intruded magmas.
  • AOYAMA Hiroshi, TAKEO Minoru  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2008-  151  -151  2008
  • 吉澤 和範, 青山 裕, 高橋 浩晃, 出原 光暉, 太田 和晃, 佐藤 一平  日本地震学会ニュースレター  19-  (4)  9  -13  2007/11/10
  • 中道治久, 渡辺秀文, 大湊隆雄, 鍵山恒臣, 及川純, 竹田豊太郎, 小山悦郎, 小林知勝, 長田昇, 辻浩, 大島弘光, 青山裕, 前川徳光, 鈴木敦生, 田中聡, 西村太志, 仁田交市, 山崎純, 萩原道徳, 山岡耕春, 山田守, 大倉敬宏, 須藤靖明, 井口正人, 清水洋, 植平賢司, 松島健, 八木原寛  月刊地球  71  -76  2007/02/01  [Not refereed][Not invited]
  • 3次元可視画像撮影に向けた無線同期装置の開発
    青山 裕  火山爆発のダイナミックス，文部科学省科学研究費特定領域研究(領域番号422)研究成果報告書(平成18年度)  290  -292  2007  [Not refereed][Not invited]
  • Murase Masayuki, Ito Takeo, Miyajima Rikio, Mori Hitoshi, Aoyama Hiroshi, Oshima Hiromitu, Yoshida Yuka, Terada Akihiko, Koyama Eturo, Takeda Toyotaro, Watanabe Hidefumi, Kimata Fumiaki, Fujii Naoyuki  Programme and abstracts the Volcanological Society of Japan  2006-  70  -70  2006/10/23  [Not refereed][Not invited]
  • AOYAMA Hiroshi, TAMEGURI Takeshi, ONIZAWA Shin'ya, SUZUKI Atsuo, MULYANA Iyan, OSHIMA Hiromitsu, MAEKAWA Tokumitsu, SHIGA Toru, YOSHIKAWA Akifumi, KOYAMA Hiroshi, NAKAHASHI Masaki, FUKUYAMA Yoshiaki  Programme and abstracts the Volcanological Society of Japan  2006-  139  -139  2006/10/23  [Not refereed][Not invited]
  • Yoshida Y, Oshima H, Mori H, Maekawa T, Suzuki A, Aoyama H, Murase M, Miyajima R, Kimata F, Uchida K, Michihana H, Shiga T, Fukuyama Y, Oikawa F  Programme and abstracts the Volcanological Society of Japan  2006-  151  -151  2006/10/23  [Not refereed][Not invited]
  • MURASE MASAYUKI, ITO TAKEO, MIYAJIMA RIKIO, MORI HITOSHI, AOYAMA HIROSHI, OSHIMA HIROMITSU, YOSHIDA YUKA, TERADA AKIHIKO, KOYAMA ETSURO, TAKEDA TOYOTARO, WATANABE HIDEFUMI, KIMATA FUMIAKI, FUJII NAOYUKI  日本火山学会講演予稿集  2006-  70  -70  2006  [Not refereed][Not invited]
  • 火山観測用ドップラーレーダーの開発−−動作試験−−
    大島弘光, 青山 裕  火山爆発のダイナミックス，文部科学省科学研究費特定領域研究(領域番号422)研究成果報告書(平成17年度)  295  -298  2006  [Not refereed][Not invited]
  • 3次元可視画像撮影装置の試作
    青山 裕  火山爆発のダイナミックス！文部科学省科学研究費特定領域研究(領域番号422)研究成果報告書(平成17年度)  291  -294  2006  [Not refereed][Not invited]
  • Yoshida Y, Oshima H, Maekawa T, Suzuki A, Aoyama H  Programme and abstracts the Volcanological Society of Japan  2005-  133  -133  2005/10/05  [Not refereed][Not invited]
  • Aoyama Hiroshi  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2005-  88  -88  2005
  • Murase Masayuki, Ono Koji, Ohta Yusaku, Nishimae Kenicni, Kariya Shinichi, Miyajima Rikio, Kimata Fumiaki, Mori Hitoshi, Aoyama Hiroshi, Terada Akihiko, Koyama Eturo, Takeda Toyotaro, Osada Noboru, Watanabe Hidefumi  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2005-  71  -71  2005
  • 火山観測用ドップラーレーダーの開発−−データ処理装置−−
    大島弘光, 青山 裕  火山爆発のダイナミックス，文部科学省科学研究費特定領域研究(領域番号422)研究成果報告書(平成16年度)  274  -277  2005  [Not refereed][Not invited]
  • 浅間火山における2004年水準測量の結果と(1935-1939-1953年に観測された)上下変動にもとづく圧力源の推定
    小野幸治, 村瀬雅之, 木股文昭, 宮島力雄, 太田雄策, 仮屋新一, 西前健一, 柏木雅生, 森 済, 青山 裕, 寺田暁彦, 小山悦郎, 竹田豊太郎, 長田 昇, 渡辺秀文  2004年浅間火山の噴火に関する総合的調査，科学研究費補助金(特別研究促進費)研究成果報告書C-18（課題番号16800002）  37  -39  2005  [Not refereed][Not invited]
  • 日本の火山性地震・微動のデータベース(共著)
    大島弘光, 青山 裕, 筒井智樹, 西村太志, 田中 聡, 藤田英輔, 熊谷博之, 中道治久, 及川 純, 大湊隆雄, 小林知勝, 武尾 実, 鬼沢真也, 高木憲朗, 中野 優, 井口正人, 為栗 健, 須藤靖明, 森 健彦, 馬越孝道, 清水 洋, 八木原 寛  日本の火山性地震・微動のデータベース  649-  2004  [Not refereed][Not invited]
  • TERADA Akihiko, SHIMANO Taketo, KOYAMA Etsuro, AOYAMA Hiroshi, IIJIMA Sei  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2004-  (0)  197  -197  2004  [Not refereed][Not invited]
  • 火山観測用ドップラーレーダーの試作−−アンテナおよび送・受信装置−−
    大島弘光, 青山 裕  火山爆発のダイナミックス，文部科学省科学研究費特定領域研究(領域番号422)研究成果報告書(平成15年度)  308  -311  2004  [Not refereed][Not invited]
  • TSUTSUI Tomoki, OSHIMA Hiromitsu, AOYAMA Hiroshi, ONIZAWA Shin'ya  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2003-  (0)  7  -7  2003  [Not refereed][Not invited]
  • AOYAMA Hiroshi, OSHIMA Hiromitsu, MAEKAWA Tokumitsu  Programme and abstracts the Volcanological Society of Japan  2002-  (2)  194  -194  2002/10/22  [Not refereed][Not invited]
  • 鬼澤 真也, 大島 弘光, 青山 裕  号外地球  (39)  14  -21  2002  [Not refereed][Not invited]
  • 2000年有珠山噴火の予測と減災情報・助言の活用（前兆地震発生から噴火開始まで）
    岡田 弘, 大島弘光, 青山 裕, 森 済, 宇井忠英, 勝井義雄  有珠山2000年噴火と火山防災に関する総合的観測研究，平成12年度科学研究費補助金（特別研究促進費）研究成果報告書（課題番号12800001）  34  -57  2002  [Not refereed][Not invited]
  • Aoyama H, Oshima H, Maekawa T  Programme and abstracts the Volcanological Society of Japan  2001-  (2)  81  -81  2001/10/01  [Not refereed][Not invited]
  • Oshima H, Maekawa T, Aoyama H  Programme and abstracts the Volcanological Society of Japan  2000-  (2)  159  -159  2000/09/30  [Not refereed][Not invited]
  • AOYAMA Hiroshi, IDE Satoshi, TAKEO Minoru  日本地震学会講演予稿集 = Programme and abstracts, the Seismological Society of Japan  1999-  (2)  P035  1999/11/09
  • AOYAMA H., IDE S., MATSUBARA M., HIRATA N., TAKEO M., SAKAI S., SAKAI K., KOBAYASHI M., HANEDA T., HASHIMOTO S.  日本地震学会講演予稿集 = Programme and abstracts, the Seismological Society of Japan  1998-  (2)  1998/10/09
  • AOYAMA Hiroshi, TAKEO Minoru, TSUJI Hiroshi, KANESHIMA Satoshi, OIKAWA Jun, GYODA Noriya  PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  1996-  94  -94  1996

Books etc

  • 北海道の地震と津波
    青山 裕 (Contributor10 火山噴火と地震)
    北海道新聞社 2012/02 (ISBN: 9784894536340) 245

Presentations

  • Shallow crustal activity observed at the crater area of Tokachidake volcano  [Not invited]
    AOYAMA Hiroshi, HASHIOTO Takeshi, TANAKA Ryo, OSHIMA Hiromitsu, SAITO Kouichiro, MICHISHITA Tsuyoshi, OKUYAMA Satoshi, JMA Sapporo
    Japan Geoscience Union Meeting  2019/05  Chiba city  Japan Geoscience Union
  • Tsutsui Tomoki, Takei Ryuichi, Tada Yuya, Moriwaki Tomoya, Aoyama Hiroshi, Aoki Yosuke, Maruyama Go
    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN  2018  The Volcanological Society of Japan
  • Near-crater observation of Tokachi-dake volcano  [Not invited]
    AOYAMA Hiroshi
    Volcanological Society of Japan, 2017 Fall Meeting  2017/10  熊本市  日本火山学会
  • 火山噴火の発生を探る〜日ロ共同火山観測研究〜  [Not invited]
    青山 裕
    2016年度地震火山研究観測センターシンポジウム  2017/03  札幌市  北海道大学大学院理学研究院附属地震火山研究観測センター
  • Woodpecker seismicity before the flank effusive eruption at Stromboli  [Not invited]
    AOYAMA Hiroshi, YAMADA Taishi, NISHIMURA Takeshi, KAWAGUCHI Ryohei, MIWA Takahiro, FUJITA Eisuke, RIPEPE Maurizio, GENCO Riccardo
    Volcanological Society of Japan, 2016 Fall Meeting  2016/10  富士吉田市  日本火山学会
  • 道内火山における地震学的研究の60年  [Not invited]
    青山 裕
    2015年度地震火山研究観測センターシンポジウム  2016/03  札幌市  北海道大学大学院理学研究院附属地震火山研究観測センター
  • Near crater observation and recent activity of Tokachi-dake volcano  [Not invited]
    AOYAMA Hiroshi, HASHIMOTO Takeshi, NISHIMURA Takeshi, ICHIKI Masahiro, KOYAMA Takao, OKADA Kazumi, TANAKA Ryo, YAMADA Taishi, OUNAGA Ryosuke, MISHIMA Wataru
    Volcanological Society of Japan, 2015 Fall Meeting  2015/10  富山市  日本火山学会
  • Seismic signal variation during the transitional phase from repetitive explosion to effusive eruption at Stromboli  [Not invited]
    AOYAMA Hiroshi, NISHIMURA Takeshi, YAMADA Taishi, KAWAGUCHI Ryohei, MIWA Takahiro, FUJITA Eisuke, RIPEPE Maurizio, GENCO Riccardo, LACANNA Giorgio
    2015 Japan Geoscience Union Meeting  2015/05  千葉市  日本地球惑星科学連合
  • Seismic swarm near Tarumaesan volcano and Ishikari-Nanbu Earthquake (MJMA5.6)  [Not invited]
    AOYAMA Hiroshi, MORI Hitoshi, HASHIMOTO Takeshi, OSHIMA Hiromitsu, MURAKAMI Makoto
    Volcanological Society of Japan, 2014 Fall Meeting  2014/10  福岡市  日本火山学会
  • Dike opening inferred from tilt change prior to the small phreatic eruption of Meakan-dake volcano, Hokkaido, Japan, in November 2008  [Not invited]
    AOYAMA Hiroshi, OSHIMA Hiromitsu
    8th Biennial Workshop on Japan-Kamchatka-Alaska Subduction Processes  2014/07  Sapporo  Institute of Seismology and Volcanology and Department of Natural History Sciences, Hokkaido University
  • Seismic swarm at Tarumaesan volcano in 2013  [Not invited]
    AOYAMA Hiroshi, HASHIMOTO Takeshi, MORI Hitoshi, OSHIMA Hiromitsu, MURAKAMI Makoto, USUI Yuji, MIYAMOTO Masashi
    Volcanological Society of Japan, 2013 Fall Meeting  2013/10  猪苗代町  日本火山学会
  • Wave properties of explosion earthquake and precursory tilt change associated with vulcanian eruptions at Lokon volcano  [Not invited]
    AOYAMA Hiroshi, YAMADA Taishi, NISHIMURA Takeshi, YAKIWARA Hiroshi, NAKAMICHI Haruhisa, OIKAWA Jun, IGUCHI Masato, HENDRASTO Muhamad, SUPARMAN Yasa
    2013 Japan Geoscience Union Meeting  2013/05  千葉市  日本地球惑星科学連合
  • インドネシア，ロコン火山における地震・地殻変動観測  [Not invited]
    青山 裕
    2012年度地震火山研究観測センターシンポジウム  2013/03  札幌市  北海道大学大学院理学研究院附属地震火山研究観測センター
  • Seismological study on precursors of the small phreatic eruptions at Meakan-dake volcano in 2006 and 2008  [Not invited]
    AOYAMA Hiroshi, OGISO Masashi
    7th Biennual Workshop on Japan-Kamchatka-Alaska Subduction Processes  2011/08  Petropavlovsk-Kamchatsky  Institute of Volcanology and Seismology FEB RAS
  • Experimental seismic survey in Ginnuma crater, Usu volcano  [Not invited]
    AOYAMA Hiroshi, NAKAJIMA Atsushi, SAITO Yu, IWAMI Yurika, YANAI Kaori, YAMADA Taishi
    Volcanological Society of Japan, 2010 Fall Meeting  2010/10  京都市  日本火山学会
  • Inter-eruptive volcanism at Usu volcano: Micro-earthquakes and dome subsidence  [Not invited]
    AOYAMA Hiroshi, ONIZAWA Shin'ya, KOBAYASHI Tomokadu, TAMEGURI Takeshi, HASHIMOTO Takeshi, OSHIMA Hiromitsu, MORI Hitoshi
    AGU 2009 Fall Meeting  2009/12  San Francisco  American Geophysical Union
  • Precursory activity of the 2008 eruption of Meakan-dake volcano  [Not invited]
    AOYAMA Hiroshi, OSHIMA Hiromitsu
    Volcanological Society of Japan, 2009 Fall Meeting  2009/10  小田原市  日本火山学会
  • Reexamination of consecutive eruption of Mt. Asama in September 2004  [Not invited]
    AOYAMA Hiroshi, TAKEO Minoru
    Volcanological Society of Japan, 2008 Fall Meeting  2008/10  盛岡市  日本火山学会
  • Tilt Change Preceding to a Small Phreatic Explosion of Meakan-dake Volcano  [Not invited]
    AOYAMA Hiroshi, OSHIMA Hiromitsu
    Cities on Volcano 5  2007/11  Shimabara  Volcanological Society of Japan
  • Simplified test on tilt response of CMG40T seismometers  [Not invited]
    AOYAMA Hiroshi
    Seismological Society of Japan, 2007 Fall Meeting  2007/10  仙台市  日本地震学会
  • A very long period seismic signal preceding a small phreatic explosion of Meakan-dake volcano, Hokkaido, Japan  [Not invited]
    AOYAMA Hiroshi, OSHIMA Hiromitsu
    2007 Japan Geoscience Union Meeting  2007/05  千葉市  日本地球惑星科学連合
  • Micro-earthquake activity at Usu volcano revealed by temporary dense observation  [Not invited]
    AOYAMA Hiroshi, ONIZAWA Shin'ya, TAMEGURI Takeshi, SUZUKI Atsuo, MAEKAWA Tokumitsu, OSHIMA Hiromitsu, MORI Hitoshi, Y, HASHIMOTO Takeshi, SHIGA Toru, KOYAMA Hiroshi, NAKAHASHI Masaki, YOSHIKAWA Akifumi, FUKUYAMA Yoshiaki
    2007 Japan Geoscience Union Meeting  2007/05  千葉市  日本地球惑星科学連合
  • Microseismicity of Usu Volcano in the dormant period (Preliminary Report)  [Not invited]
    AOYAMA Hiroshi, TAMEGURI Takeshi, ONIZAWA Shin'ya, SUZUKI Atsuo, MULYANA Iyan, OSHIMA Hiromitsu, MAEKAWA Tokumitsu, SHIGA Toru, YOSHIKAWA Akifumi, KOYAMA Hiroshi, NAKAHASHI Masaki, FUKUYAMA Yoshiaki
    Volcanological Society of Japan, 2006 Fall Meeting  2006/10  阿蘇市  日本火山学会
  • Seismic swarm and emission of high temperature gas at Tarumae volcano induced by the 2003 Tokachi-oki earthquake  [Not invited]
    AOYAMA Hiroshi
    2006 Japan Geoscience Union Meeting  2006/05  千葉市  日本地球惑星科学連合
  • A plan of development of 3D image capturing system for volcano monitoring  [Not invited]
    AOYAMA Hiroshi
    Volcanological Society of Japan, 2005 Fall Meeting  2005/10  札幌市  日本火山学会
  • Acoustic signal and ground motion observed at Mt. Usu on 31 March 2000  [Not invited]
    AOYAMA Hiroshi, OSHIMA Hiromitsu, MAEKAWA Tokumitsu
    Volcanological Society of Japan, 2002 Fall Meeting  2002/10  仙台市  日本火山学会
  • Volcano acoustic activity associated with the eruption of Mt. Usu, 2000 -Mud-pool Strombolian-  [Not invited]
    AOYAMA Hiroshi, OSHIMA Hiromitsu, MAEKAWA Tokumitsu
    AGU 2001 Fall Meeting  2001/12  San Francisco  American Geophysical Union
  • Volcano-Acoustic Feature of the Mud-Pool Strombolian  [Not invited]
    AOYAMA Hiroshi, OSHIMA Hiromitsu, MAEKAWA Tokumitsu
    Volcanological Society of Japan, 2001 Fall Meeting  2001/10  鹿児島市  日本火山学会
  • Examination of a simple fluid flow model as a source of long-period earthquake  [Not invited]
    AOYAMA Hiroshi, TAKEO Minoru
    地球惑星科学関連学会合同大会  2000/04  新宿区  地球惑星科学関連学会
  • Evolution of Earthquake Swarm Under Hida Mountains, Central Japan, in 1998  [Not invited]
    AOYAMA Hiroshi, IDE Satoshi, TAKEO Minoru
    AGU 1999 Fall meeting  1999/12  San Francisco  American Geophysical Union
  • Evolution of Earthquakes Swarm Under Hida Mountains in 1998  [Not invited]
    AOYAMA Hiroshi, IDE Satoshi, TAKEO Minoru
    日本地震学会1999年秋季大会  1999/10  仙台  日本地震学会
  • Statistics of Seismicity and Source Processes of Earthquake Swarm Around Kamikouchi, Japan, in 1998  [Not invited]
    AOYAMA Hiroshi, IDE SAtoshi, TAKEO Minoru, HIRATA Naoshi
    IUGG XXII General Assembly  1999/07  Birmingham  Internatinonal Union of Geodesy and Geophysics
  • Wave Properties and Focal Mechanisms of N-type Earthquakes at Asama Volcano  [Not invited]
    AOYAMA Hiroshi, TAKEO Minoru
    AGU 1998 Fall meeting  1998/12  San Francisco  American Geophysical Union
  • Activities and Source Mechanisms of the Series of Earthquakes Around Kamikouchi, August 1998  [Not invited]
    AOYAMA Hiroshi, IDE Satoshi, MATSUBARA Makoto, HIRATA Naoshi, TAKEO Minoru, SAKAI Shin'ichi, SAKAI Kaname, KOBAYASHI Masaru, HANEDA Toshio, HASHIMOTO Shin'ichi
    Seismological Society of Japan, 1998 Fall Meeting  1998/10  日本地震学会
  • Wave properties and focal mechanisms of N-type earthquakes at Asama Volcano  [Not invited]
    AOYAMA Hiroshi, TAKEO Minoru
    地球惑星科学関連学会合同大会  1998/04  新宿区  地球惑星科学関連学会
  • Wave properties of N-type earthquakes observed by broad-band seismometers at Asama Volcano  [Not invited]
    AOYAMA Hiroshi, TAKEO Minoru, TSUJI Hiroshi, KANESHIMA Satoshi, OIKAWA Jun, GYODA Noriya
    Volcanological Society of Japan, 1998 Fall Meeting  1996/11  大島町  日本火山学会

Association Memberships

  • JAPAN GEOSCIENCE UNION   American Geophysical Union   The Volcanological Society of Japan   The Seismological Society of Japan   

Research Projects

  • 日本学術振興会：科学研究費助成事業 挑戦的研究(萌芽)
    Date (from‐to) : 2021/07 -2024/03 
    Author : 青山 裕, 西村 太志, 田中 良
     
    初年度である2021年度は，北海道南部のしかべ間歇泉で本研究課題の開始前から実施している多項目連続観測を継続して噴出孔内の映像撮影や圧力測定を試みたほか，鬼首間歇泉で取得した熱赤外カメラ及び空気振動観測のデータ解析，霧島硫黄山の噴気観測，地下構造の深部からの熱水供給率を変化させたときの熱水流動の応答に関する数値計算などを実施した． しかべ間歇泉では，間歇泉噴出孔の保守業者の厚意により，6月および9月の作業時に業者所有の孔内撮影用カメラを間歇泉内に挿入し，孔内の状況把握や孔底深度の計測，噴出時の気泡発生状況の動画撮影等を行った．この調査により，掘削深度は約27mであり，ケーシング部分は上部の20mで下部の約7mは裸孔となっていることが始めて確認された．また，井戸の下端には熱水溜まりのような空洞は存在せず，ケーシング下端や裸孔部分の亀裂から井戸内に高温水が流入していることが明らかになった．1月には研究費で購入した圧力センサーを用いて噴出中の孔内圧力を測定し，噴出サイクルを通した井戸内圧力の時系列データを取得した．この調査時には，噴出ごとの熱水噴出体積の推定を試み，過去に見積もられた400L程度であることを確認した． 鬼首間歇泉では，間欠泉噴出時に観測した熱赤外映像および空気振動観測のデータ解析を進めた．熱赤外映像は時間的な差分を取ることで短周期変動を強調し，熱水の上方への噴出を調べた結果，周期1秒以下の調和振動が見られることを見出した．空気振動にも同様の振動が見られることから，噴出孔の極浅部で共鳴現象が起きていることが示唆された． 宮崎県の霧島硫黄山では，自然の噴気について熱赤外映像の試験観測を行った．予備的な解析では，連続的な蒸気を噴出する噴気にも調和振動的な振る舞いが認められることから，間歇泉現象や噴気現象には浅部に共鳴現象を励起する類似のプロセスがあることが示唆された．
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2018/04 -2021/03 
    Author : Aoyama Hiroshi
     
    We conducted continuous observations of ground vibration and sound waves excited by slush flow occurring on Mt. Fuji and developed a source location estimation system for seismic signals. The observation equipment was deployed mainly along the Fuji-Subaru line from December to May every year from 2018. Unfortunately, slush flows did not occur for two seasons after the start of this project, and we could not collect the data as originally planned. However, on March 21, 2021, the last year of the project, slush flows occurred along the Fuji-Subaru line, and we are waiting for the final data collection. In parallel with the field observations, we have also developed and implemented a source location estimation system for seismic signals using the spatial distribution of ground motion amplitudes, which is being tested at the Mount Fuji Research Institute and Hokkaido University.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2017/04 -2021/03 
    Author : AOKI Yosuke
     
    The goal of this study is to understand the mechanics of the emergence of a lava dome. To achieve the goal, we conducted a seismic experiment in Showa-shinzan, a lava dome emerged during the 1943-1945 eruption of Usu Volcano, northern Japan. We imaged the seismic velocity structure beneath the lava dome by seismic interferometry using ambient seismic noise. Our results image a high-velocity body beneath the lava dome, indicating that the lava dome is mainly composed of actively intruded magma, rather than passive uplift of the surface. Also, we fortuitously found previously unidentified volcanic earthquakes that may result from thermal cooling of the intruded lava. Details of these earthquakes will be investigated later.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Special Purposes
    Date (from‐to) : 2018/02 -2019/03 
    Author : Ogawa Yasuo, Kaneko Takayuki, Ominato Takao, Ishimine Yasuhiro, Matsumoto Takane, Tamaguchi Satoru, Ito Yoichi, Tsunematsu Mae
     
    Motoshirane volcano had phreatic eruption on January 23, 2018 with casualties. This study aimed at the followings: (1) elucidating the eruption mechanism, (2) monitoring and prediction of on-going volcanic activity and (3) assessment of potential lahar. Despite the volcanic tremor two minutes prior to the eruption, we could not find significant precursory seismic activity. We observed temporal tilt changes at the borehole stations and they are explained by a crack inflation and deflation. We observed no anomalous surface temperature at the new vent in March, 2018, however, from the aeromagnetic survey, the temperature of the regional volcanic area at depth seems elevated over the years. The total ejected mass was estimated as 36,000 tons which is 1/10 of that of 2014 Mt. Ontake eruption. From the chemical analyses of the ash, the ejected gas has different origin from known fumaroles. We also made risk assessment of lahar.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Research Activity Start-up
    Date (from‐to) : 2017/08 -2019/03 
    Author : Yamada Taishi, Aoyama Hiroshi, Ueda Hideki, Iguchi Masato, Tameguri Takeshi
     
    The present project proposes a method to evaluate eruption cloud volume using acoustic (infrasound) signals. The finding is that infrasound-derived cloud volume, that is obtained by infrasound signal analysis, is well correlate with buoyancy-derived volume, which derived from a mathematical model with the maximum eruption cloud height data. Difference between both estimates can be explained by time evolution of eruption cloud during ascending process. Since infrasound data can be transmitted in real-time, the method can contribute the hazard evaluation of volcanic eruption. A visual observation tool for volcanic eruption cloud synchronized GNSS time stump is also developed. Considering kinematic features of eruption cloud with video observation, accuracy of volume estimation with acoustic observation can be improved in the future works.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Special Purposes
    Date (from‐to) : 2018/10 -2019/03 
    Author : Takahashi Hiroaki
     
    Comprehensive investigation on the 2018 Hokkaido Eastern Iburi earthquake and its disaster was conducted. Mainshock rupture initiated at deepest part and major slip was occurred in 20-30km deep. Multiple simultaneous landslides in Atsuma town was induced by combination of strong ground shaking and weak sliding layer between pyroclastic fall deposit layers. Halloysite cray minerals was discovered in all sliding layers. Simulation suggested landslides might attack residential houses within 6 seconds. Observed peak ground motions in nearby area were larger than common distance attenuation model. Severe wooden house damage in Mukawa town was due to amplified seismic waves due to site effects. Sounding and boring investigation revealed filled low-density volcanic ash and higher groundwater level in liquefaction area. Electricity blackout caused severe damage in social and economic activities of Hokkaido. These scientific outcomes were explained to residents at public briefing session.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
    Date (from‐to) : 2016/04 -2018/03 
    Author : NAKAMICHI Haruhisa, OISHI Satoru, YAMADA Taishi, TERADA Akihiko
     
    We obtained the seismic and acoustic energies and durations of 2014 and 2015 eruptions of Kuchinoerabujima. We estimated the altitude of the eruption plume by a force at the seismic source and compare with the plume altitude by visual observation for the 2015 eruption. We compared seismic waveforms and tilt changes of eruptions in Japan and clarified common features of the eruptions of Kusatsushiranesan, Ontakesan and Kuchinoerabujima. We detected the radar reflection intensity corresponding to eruption plumes of Sakurajima and Shinmoedake. We estimated the plume height of the Sakurajima eruption on November 13, 2017 as 4 km by using the radar reflection intensity, although the visual plume height was unknown due to bad weather. By comparing the radar reflection intensities of the 2017 and 2018 eruptions of Shinmoedake with the plume altitudes by visual observation, we accumulated the basic data for establishing a method for estimating altitudes of eruption plumes using weather radars.
  • 広域地震観測網を用いた泥流検知手法の試験および評価
    北海道河川財団：研究助成
    Date (from‐to) : 2015/06 -2016/03 
    Author : 青山 裕
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
    Date (from‐to) : 2010/04 -2014/03 
    Author : NAKAGAWA Mitsuhiro, TAKAHASHI Hiroaki, MATSUSHIMA Takeshi, MIYAMACHI Hiroki, HASEGAWA Takeshi, AOYAMA Hiroshi, ISHIZUKA Yoshihiro, MIYAGI Yousuke
     
    Geophysical, geological and petrological research of Klyuchevskoy volcano, Kamchatka, was carried out. We installed four tiltmeters to construct the network with seismographs for monitoring of activity of the volcano. We have also continued to maintain the network, which has been working during our research period. Continuous tilt measurements detected cyclic deformation with every 10 - 20 minutes. This monitoring result enables to construct the model for the Strombolian type eruptions. On the other hand, petrological and geochemical analysis reveals that eruptive materials during the last 3000 years can be divided into two types of basaltic magma, one of which had been gradually replaced by another type of basaltic magma. In addition, although eruptive activity has continued intermittently during the last 80 years, magma system beneath the volcano has changed after each dormant period.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2007 -2009 
    Author : ONIZAWA Shinya, OSHIMA Hiromitsu, AOYAMA Hiroshi, MAEKAWA Tokumitsu, SUZUKI Atsuo
     
    Volcanic phenomena observed in four eruptions during the 20th century were compiled and characteristics of precursory seismic activities of these eruptions were compared, in order to enhance short term prediction of volcanic eruptions. We showed similarities of earlier stage of the precursory activities between the summit and flank eruptions, while there exist unique activities only before the flank eruptions. For long term prediction, seismic activities and ground deformations in dormant period were investigated. The seismic activities beneath the summit are caused by subsidence of the 1977-82 crypto-dome. Beneath Usu volcano, the basement layer gets shallower toward the north. Northward and southward migrating seismic activities before the 2000 eruption occurred along the dipping basement, suggesting the activities were constrained by the subsurface structure. Asymmetric patterns of ground deformations caused by lava and crypto-domes were related to the subsurface basement structure. Furthermore, subsurface velocity structure of Hokkaido-Komagatake volcano was revealed for future comparative studies, and a high velocity region was detected beneath the summit.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Priority Areas
    Date (from‐to) : 2005 -2006 
    Author : 青山 裕
     
    2006年度は試作機で得られた成果をもとにして,無線装置の作成を進めた.複数受信点への同報性に優れた無線装置を用いることで,トリガー発生装置とカメラの配置を自由に取ることができ,ステレオ撮影で重要となる視点間距離を大きくすることができる.また,撮影するカメラの台数も理論上は無制限に増やすことが可能となる.しかしその一方で,有線系システムでは現れなかった同期信号の遅延が生じることが予想された. 装置作成においては(有)ユニテクノ研究開発部の石川和也氏にご協力をいただいた.ユニテクノ製の特定小電力無線伝送装置は,送受信機間の距離を約2kmまで広げられることの他に,信号伝達の時間遅れがミリ秒の精度で一定となっているという特徴がある.この時間遅れ精度の保証は,カメラ同士の撮影時刻同期精度を保つ上で非常に有用である.無線同期装置のベースとしてユニテクノ製UM3型無線装置を利用した.本研究ではUM3型無線装置を1対Nの組み合わせで利用し,送信機側にGPS同期のパルス発生装置やトリガー信号のコントローラーを組み入れた.受信機側には2005年度の有線系試作時に作成済みのシャッター信号/カウンター信号分離装置を接続し,その先にカメラと収録用PCがつながれることとなる. 撮影時刻の精度を高める目的で,送信機側にGPSモジュールを搭載した.送信機は起動後のスタンバイ状態でGPS時計との同期動作を開始し,スタートボタン押下後の毎分0秒から設定されたシャッタースピードで同期信号を送出する.無線伝送による遅延時間のゆらぎを低減するために,固定データ長の固定周期で同期シャッター信号を送信する.データ送信は30fpsに相当する33.3ms毎(誤差±400μs以内)に行われる. 機器の細部調整は若干残っているが,予定年度内に計画通りの撮影装置の作成を完了することができた.

Social Contribution

  • 最近話題になった十勝岳の火山現象について
    Date (from-to) : 2020/12/17
    Role : Lecturer
    Sponser, Organizer, Publisher  : 十勝岳火山防災協議会
    Event, Program, Title : 十勝岳噴火総合防災訓練に伴う関係機関調整会議
    Governmental agency
  • 火山で観測した信号のおもしろさ
    Date (from-to) : 2020/12/15
    Role : Lecturer
    Sponser, Organizer, Publisher  : 札幌管区気象台
    Event, Program, Title : 札幌管区気象台 火山防災業務職員研修
    Governmental agency
  • 火山災害
    Date (from-to) : 2020/11/01
    Role : Lecturer
    Sponser, Organizer, Publisher  : 防災士研修センター
    Event, Program, Title : 防災士研修講座
  • 北海道大学の火山観測施設
    Date (from-to) : 2019/08/20
    Role : Lecturer
    Sponser, Organizer, Publisher  : 北海道駒ヶ岳火山防災協議会
    Event, Program, Title : 協議会総会
    Governmental agency 森町福祉センター
  • 火山で観測した信号のおもしろさ
    Date (from-to) : 2019/07/22
    Role : Lecturer
    Sponser, Organizer, Publisher  : 札幌管区気象台
    Event, Program, Title : 火山防災業務職員研修
    Governmental agency 札幌管区気象台
  • 有珠山 -20世紀の4回の噴火と火山学的研究-
    Date (from-to) : 2019/06/10
    Role : Lecturer
    Event, Program, Title : JICA 2019年度中南米地域火山防災能力強化研修
    JICA札幌
  • 火山で観測した信号のおもしろさ
    Date (from-to) : 2018/07/09
    Role : Lecturer
    Sponser, Organizer, Publisher  : 札幌管区気象台
    Event, Program, Title : 火山防災業務職員研修
    Governmental agency 札幌管区気象台
  • 有珠山 -20世紀の4回の噴火と火山学的研究-
    Date (from-to) : 2017/06/09
    Role : Lecturer
    Sponser, Organizer, Publisher  : JICA
    Event, Program, Title : 2017年度中南米地域火山防災能力強化研修
    Others JICA札幌
  • 北海道の活動的火山における噴火予知研究観測の課題
    Date (from-to) : 2016/08/26
    Role : Lecturer
    Sponser, Organizer, Publisher  : 洞爺湖有珠火山マイスター運営委員会
    Event, Program, Title : 洞爺湖有珠火山マイスター養成講座
    Civic organization 伊達市防災センター
  • 有珠山 -20世紀の4回の噴火と火山学的研究-
    Date (from-to) : 2016/06/10
    Role : Lecturer
    Sponser, Organizer, Publisher  : JICA
    Event, Program, Title : 2016年度中南米地域火山防災能力強化研修
    Others JICA札幌
  • 有珠山 -20世紀の4回の噴火と火山学的研究-
    Date (from-to) : 2014/06/16
    Role : Lecturer
    Sponser, Organizer, Publisher  : JICA
    Event, Program, Title : 2014年度中南米地域火山防災能力強化研修
    Others JICA札幌
  • 有珠山 -20世紀の4回の噴火と火山学的研究-
    Date (from-to) : 2013/06/14
    Role : Lecturer
    Sponser, Organizer, Publisher  : JICA
    Event, Program, Title : 2013年度中南米地域火山防災能力強化研修
    Others JICA札幌
  • 有珠山 -20世紀の4回の噴火と火山学的研究-
    Date (from-to) : 2012/06/18
    Role : Lecturer
    Sponser, Organizer, Publisher  : JICA
    Event, Program, Title : 2012年度中南米地域火山防災能力強化研修
    Others JICA札幌
  • 新燃岳の火山観測体制と道内火山の観測例
    Date (from-to) : 2012/02/03
    Role : Lecturer
    Sponser, Organizer, Publisher  : 北海道防災会議
    Event, Program, Title : 地震火山対策部会火山専門委員会
    Governmental agency 北海道立道民活動センター[かでる２．７]
  • 有珠山 -20世紀の4回の噴火と火山学的研究-
    Date (from-to) : 2011/06/20
    Role : Lecturer
    Sponser, Organizer, Publisher  : JICA
    Event, Program, Title : 2011年度中南米地域火山防災能力強化研修
    Others JICA札幌
  • 有珠山 -20世紀の4回の噴火と火山学的研究-
    Date (from-to) : 2010/07/17
    Role : Lecturer
    Sponser, Organizer, Publisher  : JICA
    Event, Program, Title : 2010年度中南米地域火山防災能力強化研修
    Others JICA札幌

Others

  • 2014/03 -2014/03 北海道における火山に関する研究報告書・第15編 十勝岳火山地質・噴火史・活動の現況および防災対策 第II版
  • 2004/03 -2004/03 日本の火山性地震・微動のデータベース

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